Some problems in 10.8

Some problems in 10.7


Supports iCloud

Secured by Gatekeeper

Supports retina graphics

CoolBook icon

Available on the Mac App Store
Not available on the Mac App Store

CoolBook lets you monitor CPU frequency, voltage, and temperature of CoreDuo/Core2Duo processors.

Version 2.22
Developer Magnus Lundholm
Status Some problems

0 ratings

Works with same fix on both LION(as of 10.7.4) and MOUNTAIN LION(as of 10.8.0).

1. Install Coolbook
2. Add SleepEnabler file to the system with Kext Helper. and
3. Remove the files "AppleIntelCPUPowerManagementClient.kext" and "AppleIntelCPUPowerManagement.kext" from "/System/Library/Extensions"
4. Restart

Archived comments

No comments.173 comments

[ David]DavidAnonymous 05 Mar 2012 03:37

I can confirm that Coolbook works with 10.7.3 on MBP 2007 as Horst stated

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[ andy]andyAnonymous 19 Mar 2012 21:57

Running 10.7.3, and I am following the recipe in notes on the top of the page, but changed the kext to ( ( as per Horst recommendation. The kext installed and restarted fine, but can't get coolbooks to start. It says 'Coolbooks installation failed' before it launches, but the app still opens. However if I quit it, and launch it again, I get the error message (installation failed), and all my changes are gone. @Horst: Step by step how did you install it?

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[ andy]andyAnonymous 21 Mar 2012 07:55

Can sergio or horst please describe how they did it? I follow the description at the top, but use ( ) instead of the kext named in the description. I also delete the appleintelcpupowermanagement kexts and reboot, but still gets this message:

How do you know it's working?

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[ ]andy400 21 Mar 2012 08:01

@sergio and @horst: can please share a littlebit more in detail how you did it?

I followed the list under, but changed the SleenEnabler with the latest verison from ( Still get this message: .

How do I know if it's working?

1. Install Coolbook
2. Install Kext Helper* -
3. Add SleepEnabler file to the system with Kext Helper. -
Note that using the older version of SleepEnabler may cause kernel panic.
4. From "/System/Library/Extensions" remove the following files:
AppleIntelCPUPowerManagementClient.kext AppleIntelCPUPowerManagement.kext
5. Restart

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[ andy]andyandy400 21 Mar 2012 14:50

sorry for my triplepost. I got it working afterall. followed this tutorial: and used the kext @horst recommended. anyone knows if coolbook need to be running in the dock for it to be working?

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[ Twotimer]TwotimerAnonymous 28 Mar 2012 16:15

Why does everybody keep saying it works with Lion when in fact it doesn't, at least the way it did with SL?

Yes, you can install it, remove/add kexts, you might even see the frequency/voltage reports in the menubar. So it "sort of" works.

But in reality (and I believe it's not just in my case with 2007 Core2Duo MBP) it actually does a worse job than stock kexts. Battery life is worse (in my case 3h30m vs 4h20m, CoolBook vs Native), that's for sure.

CoolBook doesn't seem to be able to undervolt at lower frequencies. For example, when I set 600Mhz/0.7750V as the lowest combination, it still sticks at 800Mhz/0.850V. When idling on stock kexts, I notice 0.7-something-V in the istat sensors report.

The only point trying to use CB is when you constantly run your mac at max GhZ and just want it to run a bit cooler.

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[ Peter]PeterAnonymous 06 Apr 2012 04:27

Please Respected Magnus!
Help us who have purchased your software online, all paid and have lion 10.7.3 2011 macbook air and coolbook will not work! please at least put up on your site what os it works with and what it doest work with! Basic honesty!Please forgive me if im mistaken but, i feel cheated completely.
now please i will have to refund or stop payment. goodluck on this software and all the best wishes

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[ nurbs999]nurbs999Anonymous 25 Apr 2012 12:00

@Horst: does your cpu even get down to 0.7 on idle with coolbook enabled?

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[ David]DavidAnonymous 10 May 2012 00:32

10.7.4 has been out. waiting for a new sleepenabler…

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[ Horst]HorstAnonymous 14 May 2012 14:51

The SleepEnabler.kext from the download above works under 10.7.4 as well.

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[ Yohat]YohatAnonymous 16 May 2012 17:17

Works under 10.7.4.

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[ marco]marcoAnonymous 02 Jun 2012 09:10

any compatibility info with 10.7.4 ? 2008 mbpro ?

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LeonLeonAnonymous 26 Jun 2012 07:20


You dont need to do any of the above - simply use this fix:

.. and you can still update after using it.

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[ Works for me]Works for meAnonymous 30 Jun 2012 06:58

Running Lion 10.7.4 on Late 2007 MBP 2.4GHz
*Most important is to uninstall CoolBook first

1. Uninstall CoolBook
2. Delete files "AppleIntelCPUPowerManagementClient.kext" and "AppleIntelCPUPowerManagement.kext" from "/System/Library/Extensions"
3. Install Kext Helper, and Sleep Enabler, then use Kext Helper to install Sleep Enabler
4. Restart
5. Reinstall CoolBook, activate/add permissions, set temps & MHz
6. Restart
7. Enjoy as if you're still running Snow Leopard!

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[ Not Magnus but I bring explanation.]Not Magnus but I bring explanation.Anonymous 31 Jul 2012 07:18

Coolbook is dead, and will be forever. AppleIntelCPUPowerManagementClient.kext now includes something called C and P states. Hackintosh users will be familiar with this (and actually are far far more knowledgeable about OSX than every Mac user due to having to tinker to get things working).

C and P states are for Intel's Speedstep and Turbo Boost independent over clocking features, much in the same way that Apple disabled smcFanController by constantly recalculating and resetting OSX's desired fan speed (and overriding the fan speed set by the program in seconds) C and P states erase the action carried out by CoolBook. Removing them is an option but that instantly breaks functionality with Intel i3/5/7 as they need them to scale power states correctly.

More importantly, if Intel roll out a new processor tomorrow, and the code for that CPU is added to a non-exisistant kernel extension (the one you swapped for sleep enabler) or the EFI (sleepenabler.kext is actually designed for hackintoshes) then you could be faced with kernel panics on startup that won't disappear with a reinstall unless you format your hard drive or CLI delete it in single user mode.

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[ David]DavidAnonymous 11 Aug 2012 09:13

The new sleepenabler works great with 10.7.4!

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[ jef]jefAnonymous 12 Aug 2012 21:42


I got a pb, I forget to uninstall Coolbox before upgrading to 10.8 now, i have a kernel error and I can just use my windows boot from my mac. any idea how I can fix it ?
thank you everyone

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[ pavel]pavelAnonymous 20 Aug 2012 05:49

how remove these files:
AppleIntelCPUPowerManagementClient.kext and AppleIntelCPUPowerManagement.kext
from terminal? i am boot from recovery flash drive now, because kernel panic:(

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[ Horst]HorstAnonymous 22 Sep 2012 07:53

Has anyone tested Coolbook on 10.7.5?

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[ Works for me (now using 10.7.5)]Works for me (now using 10.7.5)Anonymous 01 Oct 2012 21:50

When I updated to 10.7.5 (from 10.7.4) I had to uninstall/reinstall Coolbook to make it work again, using the same steps that worked for me in my earlier post:

Works for me on 29 June 2012, 23:58
1. Uninstall CoolBook
2. Delete files "AppleIntelCPUPowerManagementClient.kext" and "AppleIntelCPUPowerManagement.kext" from "/System/Library/Extensions"
3. Install Kext Helper, and Sleep Enabler, then use Kext Helper to install Sleep Enabler
4. Restart
5. Reinstall CoolBook, activate/add permissions, set temps & MHz
6. Restart
7. Enjoy as if you're still running Snow Leopard!

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[ David]DavidAnonymous 07 Oct 2012 12:42

Where did you get the Sleepenabler.kext for 10.7.5?

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[ darksnake]darksnakeAnonymous 25 Oct 2012 14:14

anyone updated successfully to 10.8.2? Im now on 10.8 and would like to update to 10.8.2 to get more battery life

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Lion (10.7) Comments

[ lemka]lemkaAnonymous 11 Mar 2011 00:07

any help with this, for me critical app for cooler macbook AIR

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[ felix]felixAnonymous 18 Apr 2011 09:24

Just found out too.. in Developer Preview 1 I was at least able to set it manually, but now even thats impossible

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[ George]GeorgeAnonymous 05 May 2011 10:44

No Solutoin yet? This is THE most important app for me… without it my Mac now even turns itself off because of the heat sometimes

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[ Stefan]StefanAnonymous 22 Jun 2011 20:28

Also important for me… I've already written a mail to the author two weeks ago. No response yet. :( I've bought the software 3 weeks ago.

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[ iMax]iMaxAnonymous 01 Jul 2011 21:01

GM Lion is out? any news?! :(

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[ Geoffrey]GeoffreyAnonymous 04 Jul 2011 06:42

The author has ensured me that V3.0 will be available soon for a $5 upgrade fee.

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[ iMax]iMaxAnonymous 04 Jul 2011 10:35

thank's Geoffrey :) this app is a must have for my MacBook :P

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[ Stefan]StefanAnonymous 20 Jul 2011 12:18

Thanks from me too. Awaiting the new version. $5 is a fair and affordable upgrade price.

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[ Yousif Abdullah]Yousif AbdullahAnonymous 20 Jul 2011 15:43

Good to hear someone has reached out to Magnus. Waiting for V3.0, this is definitely an important app.

$5 is doable, we all paid $30 for Lion anyway, right? ;)

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[ Roman]RomanAnonymous 20 Jul 2011 16:14

anybody know the release date ?

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[ MBH]MBHAnonymous 21 Jul 2011 14:01

i got it working in Lion. standby its not working though, but its better than the air runs hot :)

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[ ]Anonymous 21 Jul 2011 14:43

Cool, but what does "standby its not working" mean? :(

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[ MJD]MJDAnonymous 21 Jul 2011 15:19

Has anyone heard anything on this at all? Emailed Magnus but can't see an update anywhere.

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[ nurbs999]nurbs999Anonymous 21 Jul 2011 22:05

@MBH: How did you get it working?

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[ MJD]MJDAnonymous 22 Jul 2011 06:25

Yep @MBH how did you get it to run in LION? Was that V2.22?

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[ Fransisco Miranda]Fransisco MirandaAnonymous 22 Jul 2011 07:24

@MBH: Please, tell us how did you get it working on Lion! My Air is nearly unusable without undervolting.

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[ MBH]MBHAnonymous 22 Jul 2011 10:38

I will try.. :)

First i will say that I'm writing this on a Macbook Air Rev A without coolbook installed, and it runs ok. around 70 C .

a few days ago i changed the thermal paste on the air, and it helped a lot, before that i could not use the Air without CoolBook!

Im at work, i'll try to make a guide when I'm home or in the evening. (I'm from Denmark, so its 12:37 PM right now.

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[ Fransisco Miranda]Fransisco MirandaAnonymous 22 Jul 2011 11:33

@MBH: Tak! (This is the only one Danish word i know ;)
My Air turned off itself 2 times in the last 2 days (after installing Lion), so i am desperately seeking for ANY solution. I emailed Magnus yesterday, but no answer yet.
I will buy some high quality thermal paste this afternoon, and give it a try.

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[ MBH]MBHAnonymous 22 Jul 2011 11:57

værsgo! ;)

good idea. I used arctic silver 5 its one of the best!

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[ Fransisco Miranda]Fransisco MirandaAnonymous 22 Jul 2011 21:27

@MBH: Wow, my Air is back to life! Thanks again for your idea!
I bought Arctic Cooling MX-3 cooling paste, this was the most expensive one at the wholesale store (EUR 8,40 for 4g). After melting (5-10 minutes after first start), my CPU is 20-30 degrees (!!!) cooler than before. The old paste on the CPU was burned and dried out.
Now, i can even do the worst with my Mac: watching youtube HD using Flash, without thermal shutdown.
I never thought that there is so much difference between thermal pastes.

So, thanks to you, i can wait for Magnus to finish CoolBook update without turning back to Snow Leopard. :) (CoolBook gave me 45-60 minutes of extra battery time)

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[ MBH]MBHAnonymous 23 Jul 2011 10:09

its working!

i`ll post how i did it later! :)

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[ Anonymous]AnonymousAnonymous 23 Jul 2011 11:04

No, do it noooow :)

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[ Ruslan]RuslanAnonymous 23 Jul 2011 15:17

By uninstalling and reinstalling Coolbook (its driver, everything) it begins to work again. The coolbook driver fails simply because it's deleted by the installation of Lion, I believe.

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[ Blacky]BlackyAnonymous 23 Jul 2011 19:48

Confirmed, it's working :)

CoolBook Preferences
Install Lion
Install Coolbook
Enter Registration
Setup Coolbook

That was far easier than expected!!!

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[ Blacky]BlackyAnonymous 23 Jul 2011 20:05

Uhm, actually no, it doesn't work. After reinstalling I can setup the frequencies and everything, testing also works fine, but Lion continues to use the default voltages…

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[ Mike]MikeAnonymous 23 Jul 2011 20:49

Nope, not working. If you uninstall it, it will then re-install properly, but will revert to default voltages immediately after finishing the auto-test when you click Save.

This is the exact same behavior exhibited after the switch to Snow Leopard, with the then-current version of Coolbook.

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[ David]DavidAnonymous 24 Jul 2011 09:57

It is said that Lion requires kernel extensions be compiled with XCode 4.1 with specific 10.7-only headers. :-(

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[ MJD]MJDAnonymous 24 Jul 2011 11:46

@Blacky and @MBH working for me also after a reinstall.

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[ WCT]WCTAnonymous 24 Jul 2011 16:51

not working on my macbook, same situation as Blacky and Mike

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[ Fransisco Miranda]Fransisco MirandaAnonymous 25 Jul 2011 08:23

The situation here is same, can set the freqs and voltages, can test, but after saving the voltages are the "factory" settings.
I tried to uninstall-reinstall, etc, does not work.

But, as @MBH recommended, re-applying some really high quality thermal paste on the CPU will make WONDER! (I used "Arctic Cooling MX-3" brand) The old paste is dried out, and not conducting heat to the fan. If you don't know how to do this, it's worth to go to a good computer service and ask for carbon based thermal paste.
I know, this is not the exact solution for this question, but there will be no more thermal shutdown.

Magnus, if you ever read this, PLEASE do something with CoolBook to work with Lion! ;)

(Sorry for my poor english)

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[ JPP]JPPAnonymous 26 Jul 2011 01:16

Same here on my MBA 1.8. It would be nice if Magnus Lundholm would chime in here. He hasn't responded to any of my emails. Anyone have any luck with getting a response?

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[ MBH]MBHAnonymous 26 Jul 2011 01:21

I got it working with sleep!

install Coolbook
Remove AppleIntelCPUPowerManagementClient.kext & AppleIntelCPUPowerManagement.kext in /system/library/extensions
install Sleepenabler with kext helper b7 (Google)

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BirdmanBirdmanAnonymous 26 Jul 2011 09:23

Hi! MBH,

Thanks for the good news!

Any disadvantage to disable/remove the subject extension in Lion?

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[ MBH]MBHAnonymous 26 Jul 2011 09:55

No, not at all. Just don't delete the files, make a backup.
haven´t had any problems with it.
but you should expect a longer boot the first time after removing the files thats all.

Hope you all can get it to work!

You can write to me if you got any problems installing. moc.liamg|purjeohbm#moc.liamg|purjeohbm

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[ nurbs999]nurbs999Anonymous 26 Jul 2011 10:14

Confirmed, partially.

I tried your workaround and the voltages and clock settings from coolbook get used by the system. I have a MacBook2,1 (Early 2006) with a C2D 1,83Ghz. but I recognized one disadvanced:
By default, the AppleIntelCpuPowermanagment.kext lowers the voltage of the cpu down to 0.775V on idle at 996Mhz. Coolbook doesn't do this anymore. My cpu is stock at the voltage I set.
It used to work with SL.

But anyway, thanks a lot!

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[ Fransisco Miranda]Fransisco MirandaAnonymous 26 Jul 2011 10:55

Working! It's Working!!!

@MBH: You saved my day, again! Thanks.

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[ Ruslan]RuslanAnonymous 26 Jul 2011 23:25

Oh you're right, a reinstall doesn't work, sorry :/

Great find, MBH!! I can confirm mine works as well, although nurbs999 raises a good point, how would I check if the same is happening on my 15" Penryn, early 2008 Macbook Pro.

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[ Sascha]SaschaAnonymous 27 Jul 2011 05:54

Sleep mode doesn't work on MacBookAir3,2 (Late 2010) :(
Clean Lion install

Coolbook settings work fine, but when I put my mac to sleep it doesn't wake up any more.

P.S. After deleting both kext (AppleIntel…) I copied "SleepEnabler.kext" into /System/Library/Extensions. Is it correct?

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[ Bill]BillAnonymous 27 Jul 2011 06:04

Do NOT try what MBH has suggested without performing a prior backup.

The procedure is irreversible, and your Macbook may never be able to sleep again until you do a full OS restore.

Also frequencies revert themselves back to original Apple values after a while even when Coolbook works.

Wait for an update.

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[ Sascha]SaschaAnonymous 27 Jul 2011 06:17

got it working

I haven't properly "installed" SleepEnabler.kext. You have to "chmod" and "chown" the file after copying.

See how to install kernel extensions here:

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BirdmanBirdmanAnonymous 27 Jul 2011 07:10

Hi! Sascha,

Could you share what the correct procedure/steps/command to make your CoolBook working?


Where is the CoolBook support?

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[ MBH]MBHAnonymous 27 Jul 2011 12:06

Just use kext helper to install the kext!

Mine is still working great :)

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kevin paquetkevin paquetAnonymous 27 Jul 2011 14:08

I can confirm that the fix written above is working for me exceptionally well!

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[ Birdman]BirdmanAnonymous 27 Jul 2011 14:15

Hi! Kevin,

Would like to ask if you need to uninstall/remove first the CoolBook which was previous installed and ran in the 10.6.8? Or, you simply keep it there after upgrading to Lion and follow the workaround instruction for enabling the CoolBook?

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[ matthias]matthiasAnonymous 27 Jul 2011 14:22

when i do this, after restart cookbook say every time that cookbook installation failed
and no settings saved

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Kevin PaquetKevin PaquetAnonymous 27 Jul 2011 14:37

Hello Birdman,

I have been quite desperate with this App to have it working. I tried uninstalling and reinstalling it several times yesterday with no luck.

I then decided to just leave the App installed and my settings the way they are (even though it shows 2.66ghz/1.125V on my end despite the way lower settings)

Then I read this thread here and followed the instructions given above and everything seems to work pretty well so far.

A huge difference between 100 Degree Celsius and 70 Degree Celsius when I start up any CPU/GPU intense App or game.

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Kevin PaquetKevin PaquetAnonymous 27 Jul 2011 14:40

I've had that issue before, too. What I did back then was the following:

1. Completely uninstall the app (with AppCleaner or AppZapper)
2. Reinstall

I've always got into trouble when I tried to edit settings with another user account aside from the one I used for installing the App.

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[ Birdman]BirdmanAnonymous 27 Jul 2011 14:58

@Kevin Paquet

Thanks for the sharing.

So, let me wrap it up for your steps:

1. Uninstall the CoolBook to get rid of the error mentioned by matthias
2. Reinstall CoolBook
3. Remove two kext mentioned in Notes in the top of this discussion
4. Use kext helper to intall the needed SleepEnabler as mentioned by MBH
5. Restart and working

Kindly advise!


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[ ]kevinpaquet 27 Jul 2011 15:03

That's exactly what I did! I hope it'll work as smoothly for you too. I anticipated your reply before I head to bead since it's getting late here in the Philippines. Good luck, Birdman!

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[ Birdman]BirdmanAnonymous 27 Jul 2011 15:32

Hi! Kevin,

Thanks for the confirmation.

Will do the instruction tomorrow.

Night night!

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[ David]DavidAnonymous 27 Jul 2011 16:24

As Bill claimed the procedure is irreversible above, it is concerning me. Is it ok to remove AppleIntelCPUPowerManagementClient.kext and AppleIntelCPUPowerManagement.kext? I guess deleting these files may cause more than just lack of two files, like unregistering them from the system. When revised CoolBook becomes available later, can I restore them?

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BirdmanBirdmanAnonymous 28 Jul 2011 01:50

Hi! All,

Just to confirm that the procedures provided by MBH is working on my MacBook C2D.

For those who would like to make the CoolBook work under Lion, please make sure you make a back up for your setting in /System/Library/LaunchDaemons/se.coolbook.switcher.plist

After install the CoolBook together with the two kext, do a restart, overwrite the se.coolbook.switcher.plist which you just backup and run the CoolBook to save the setting. You may need to restart it to make it take effect!

Good luck!

I am going to do the same thing to my wife's MacBook!

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[ Birdman]BirdmanAnonymous 28 Jul 2011 01:52

BTW, are we going to do it again when 10.7.x coming???

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Kevin PaquetKevin PaquetAnonymous 28 Jul 2011 03:02

It depends if these files that we deleted will be restored and if the file we added is going to be removed, I guess.

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[ matthias]matthiasAnonymous 28 Jul 2011 09:22

many thanks, now it work, but i can´t set voltage under 1V under snow leopard i have the choice to set 0.9…V but now is the lowest voltage is 1V
it´s a problem with my config or have another the same problem

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BirdmanBirdmanAnonymous 28 Jul 2011 11:16

Hi! matthias,

Please try to turn off and on for the Throttling and Save the setting. CoolBook will ask you to test before saving! Just watch if the your setting of voltages have changed during the test. Then restart your Mac to see if it works or not?!

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[ matthias]matthiasAnonymous 28 Jul 2011 12:10

hello birdman,
i can´t select voltages below 1V because it´s not show voltage under 1V ;(
and i see now, he didn´t accept any changes. no error message but when i try to set only 1 profil, let say 2400mhz and voltage 1,025V he ignore this

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[ Birdman]BirdmanAnonymous 29 Jul 2011 00:30

Hi! mattias,

Is the CoolBook working before under 10.6.x?

Is the CoolBook installed properly without any error using the instruction above?

Is the CoolBook activated with the code?

Please try to remove the CoolBook again using the CoolBook's Uninstall button and reinstall again!

Where is Magnus!!!

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[ ]Anonymous 29 Jul 2011 09:56

yes it´s work nice with 10.6.x
now no error message come and no function ;(

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Lucas HungaroLucas HungaroAnonymous 29 Jul 2011 18:33

I managed to get it working with the kext fixes but I have to keep it open all the time. If I close the app (and when I restart the machine) the settings are lost.

Is this a limitation right now or it happens just to me?

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[ Max]MaxAnonymous 30 Jul 2011 00:24

Be patient, email the author, and I'm sure he'll update it soon enough. Until then, I'm just not going to run Coolbook on my 11" Air.

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[ Birdman]BirdmanAnonymous 30 Jul 2011 01:40


Please try to copy the original working setting in to the folder I mentioned in my post and disable/enable CoolBook to see if any help.


How you so sure? Any feedback/reply from Magnus lately? I have wrote him more than five mails before and after Lion launch but getting no response. Even a email to say he is working on should be ok to me! Too bad, he used to be very supportive people like me who bought two licenses from him!

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[ David]DavidAnonymous 30 Jul 2011 03:48

Snow Leopard was released august 28, 2009. And CoolBook supported it from november 17, 2009. It took almost 3 months to support 10.6, not counting developer preview period.
Maybe we have to wait much longer than we expected.

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[ David]DavidAnonymous 30 Jul 2011 03:52


Before CoolBook supported 10.6, I had sent several emails to Magnus and there was no reply. I don't think he is supportive at least for these days.

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[ Birdman]BirdmanAnonymous 30 Jul 2011 08:15

@ David,

No problem!

It does not matter how long the Lion version CoolBook will come out.

It is simply the sign and response to Magnus's customers us saying he is doing something and which may need 12 months. It is fine with me for at least the message like that!

Even better if he want me to beta test his CoolBook for verification the compatibility with Lion.

But we do receive any word from him these days!

You see people like matthias still has problem not able to get it worrk with the procedures shared at this discussion board, not to mention now it is summer season and it is pretty warn in Asia!

We indeed need the cool stuff here!

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[ Birdman]BirdmanAnonymous 30 Jul 2011 08:16

i mean :

We do NOT receive any word from Magnus!

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[ ]Anonymous 31 Jul 2011 10:28

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[ Jesse]JesseAnonymous 02 Aug 2011 15:35

The instructions here worked for me, with one possible exception. I can't remember if this was the case before, but I can't get voltages below .85 V (which I've paired with 1600 MHz). I can set lower pairs, but all I get is lower MHz, still at .85 V. In fact, as I write this, I haven't even set a pair below 1600 MHz, but CoolBook says I'm running at 1200 MHz & .85 V. Kinda frustrating. (I assume there's no advantage to the lower clock speed if I don't get lower voltage out of it, right?)

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[ WSJ]WSJAnonymous 02 Aug 2011 19:16

I followed these instructions for removing the AppleIntelCPUPowerManagementClient.kext and installing the Sleepenabler.kext version and re-installing Coolbook. I thought it was working fine and certainly it was working for about a day. Then this morning after starting up my MacBook AIr rev.A Coolbook was not operational. The system would throttle but under "volt" settings were ignored and the temperature climbed above the limit until the computer just shutdown, i.e., overheated and turned itself off.

Has anyone else had this working only to find it stop?

Also, pls. note that the Coolbook website now states that Coolbook doesn't work with 10.7, I wonder if the author of the software is saying that it will never work???

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[ GMarc]GMarcAnonymous 02 Aug 2011 19:26

@ jesse

I tested this on Snow Leopard on macbook5.1, to unlock voltage:

1. open coolbook and disable it (coolbook active)
2. restart
3. open terminal and paste this:

defaults write se.coolbook.CoolBookController2 LoopCnt 10

4. restart
5. open coolbook, and look if lower voltages are available.
6. Set voltage, active coolbook and restart.

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[ Jesse]JesseAnonymous 02 Aug 2011 21:52

Thanks GMarc. I followed your instructions, and now the available range is reduced: there's only one voltage under .85 V, namely .8375 V. Alas, the problem persists. I can map 1400 MHz to .8375 MHz, but both during the test and after being set, voltage will never go below .85 V.

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[ David]DavidAnonymous 03 Aug 2011 03:29

Magnus officially declared CoolBook does not work with Lion on its homepage. :-(

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[ David]DavidAnonymous 04 Aug 2011 20:43

For your information, DO NOT copy those two power management extensions of Snow Leopard over Lion. It will cause kernel panic.
In case you did it, boot into recovery partition of Lion by holding option key, open the terminal and remove them.

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[ Yousif Abdullah]Yousif AbdullahAnonymous 04 Aug 2011 23:23


I reached out to Magnus and received a response from him (promptly, I may add). Below is the email in all its entirety:

Hej Yousif,

I'm still trying to figure out a way to make CoolBook for Lion, but I may never find a solution.
So yes, I'm still working on CoolBook 3.



3 aug 2011 kl. 13.03 skrev Yousif Abdullah:
- Hide quoted text -

Hej Magnus,
A quick question regarding CoolBook development — "CoolBook does not work with OS X 10.7 Lion". I have read at MacRumors forums and elsewhere that you have indeed promised an update (v3.0) to support OS X Lion. Is this the case or will CoolBook not support Lion? The statement in your website makes it look as if CoolBook development has halted and will not be updated. Thank you.

It seems as if the problem is bigger than thought. I'm sure Magnus does his best to fix CoolBook as soon as possible, so be patient. Also… I personally find CoolBook a very good utility, but nowhere did Magnus promise support for Lion beforehand — if you're having issues, be kind enough to revert to Snow Leopard until a new version is out. Crying and bitching "where is Magnus?" will certainly help nobody. I understand that you have paid $10 for the app, but so have I. Fact is, there is no utility like CoolBook for the Mac, so if you can't live without it — use something that works with it.

Having that said, it's nice that the community found a workaround. I didn't get it to work, but it's a start. Have a nice day. ~Yousif.

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[ Sascha]SaschaAnonymous 05 Aug 2011 13:36

Does this workaround really work? I mean, it seems like it would work, but I'm not really sure.

Maybe this workaround just lets coolbook think it works and shows the configured values, but actually the cpu is still running the default value.

Can somebody test and definitely confirm, that the temperatures are lower, that at the default values?

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[ nurbs999]nurbs999Anonymous 05 Aug 2011 14:44

Yes, the workaround is working. Temps are lower, battery time is longer under heavy load and iStatMenu is reporting cpu voltages set by coolbook. but as i mentioned before, the AppleIntelCPU kexts are working better at idle.

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[ sscss]sscssAnonymous 05 Aug 2011 14:54

Hi nurbs999, how do you monitor cpu voltages with IStatMenu?

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[ nurbs999]nurbs999Anonymous 05 Aug 2011 15:17

@sscss: under "sensors" you have to scroll down. there are plenty of voltage sensors.
One is "CPU (V)"

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[ nurbs999]nurbs999Anonymous 05 Aug 2011 15:24

if magnus is reading this thread, he could probably tell us where the problem with lion is. perhaps some other kext developers are able to help him.

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[ Darksnake]DarksnakeAnonymous 07 Aug 2011 01:04

Did the trick using coolbook 2.16

I can't get my MBP 5,1 lower than 0,95V.. I can select down to 0,775V but it stays at lowest 0,95V

Any solution?

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[ Blacky]BlackyAnonymous 07 Aug 2011 10:20

@Darksnake: Same here, for me it's 0.925 though. Before activating, 0.925 was the default setting for the lowest frequency, so that might be related. I can set voltages below 0.925, but the voltage won't drop below that. Anything higher than that works properly, though.

Weirdly enough, iStat Menus shows vastly different voltages:

798 MhZ, Set 0.755, Coolbook shows 0.925, iStat Menus shows 0.91
1596 MhZ, Set 0.900, Coolbook shows 0.925, iStat Menus shows 0.88
2128 MhZ, Set 0.925, Coolbook shows 0.925, iStat Menus shows 0.89

The voltages iStat Menus shows are definitely lower than without Coolbook, so it is definitely "kinda" working.

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[ Darksnake]DarksnakeAnonymous 07 Aug 2011 21:07

@ Blacky strange voltage shown in istat.. Mine value's shown were correct in istat..
Today i uninstalled the kext and installed the 2 lion kext back. The voltage on Lion going way lower to 0,77V where coolbook lowest was 0,95V on my MBP 5.1 C2D 2.8 Hope that coolbook can soon take advantage of the new Lion kext!

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[ Blacky]BlackyAnonymous 08 Aug 2011 06:09

I'm quite torn between the Lion kexts and a badly working Coolbook. During high performance tasks Coolbook is way better. More or less modern games like StarCraft 2, for example, lag like hell with Apple's standard kexts, probably due to an overheating CPU (downright unusable). As stated before, during standard tasks, Apple's kexts are better. Meh. seems to be a working solution for Lion, open source, but sadly only optimized for 2008's MacBook Air.

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[ Ania]AniaAnonymous 09 Aug 2011 15:28

But looks like I'm not a developer, and i don't have idea how to build this. Can somebody do this for me please?

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[ nurbs999]nurbs999Anonymous 09 Aug 2011 17:00

@Blacky: thanks for the tip. I just tried xnu-speedstep-air and it only runs great under heavy load (both cores at 100%) or in idle. If i run a single thread using only one core the default voltages are used…

@Ania: You have a description how to build and load xnu-speedstep-air on the github page

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[ Camilo]CamiloAnonymous 09 Aug 2011 17:17

I have a Macbook Air from early 2008. I tried the xnu-speedstep-air linked by Blacky and it didn't work for me. I followed carefully the instructions, but sometimes it simply did work, and sometimes suddenly it was going back to the default settings and I was having again the kernel overload problem. In contrast, with the other fix suggested here, all has worked very well for me. Not problems at all. Indeed I feel the system is even more responsive than in Snow Leopard in things like HD video playing, maybe just a perception. I noticed as well that CoolBook shows that is assigning 0.9v to all the different frequencies. I decided to leave it that way, but not sure that what CoolBook is showing is really the true. I tested the temp limit function and it is working for me as well.

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Rob OudendijkRob OudendijkAnonymous 14 Aug 2011 21:42

After struggling weeks with LIon on my Balckbook it seems that the hack works fine for me. Also CoolBook reports correct values, something it had never done before even under snowleopard. Full rendering with Modo does not allow the CPU to go over the 70 degree Celsius as aI setup in the menu.

Thank all for this post.

I can not image, with Apple controlling the hardware and the software they mess up this elementary function.

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[ David]DavidAnonymous 16 Aug 2011 08:49

The voltage setting is set by Intel and also guaranteed by Intel. It is not Apple's fault.

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[ Geoffrey]GeoffreyAnonymous 16 Aug 2011 14:58

Loading the sleepenabler.kext on my MacBook Pro 13" 2010 caused a kernel panic. Following a forced shutdown and restart, CoolBook is indeed active but I can no longer enter sleep mode. I've gone back to Snow Leopard until a reliable solution becomes available.

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BirdmanBirdmanAnonymous 16 Aug 2011 23:30


Just a warning for those who would like to update to the latest 10.7.1.

I got kernel panic right after updating and restart my MacBook 3,1.

The error message is "Version mis-match between Kernel and CPU PM"

I am now looking for your help to solve this problem!

Any way to restart it without the kernel panic and remove the related next?

Many thanks!

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[ Chris]ChrisAnonymous 16 Aug 2011 23:38

Same problem.
I've not found any solution ATM.

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JesseJesseAnonymous 17 Aug 2011 00:16

I was fortunate enough to have another bootable partition. Starting up in it, all I had to do was remove Sleepenabler.kext. I also uninstalled Coolbook and put back AppleIntelCPUPowerManagementClient.kext and AppleIntelCPUPowerManagement.kext. And now my Macbook is noisy again. :(

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[ David]DavidAnonymous 17 Aug 2011 00:20

DO NOT upgrade to 10.7.1. Wait for updated SleepEnabler.kext.

If you upgraded already, boot into recovery partition of Lion by holding option key, open the terminal and do this:
rm -rf /Volume/Macintosh HD/System/Library/Extensions/SleepEnabler.kext

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BirdmanBirdmanAnonymous 17 Aug 2011 02:06

Hi! David,

Thanks for the great tip.

Actually, I have managed to get rid of the kernel panic after using a bootable USB disk and removing the SleepEnabler.kext.

As for the CoolBook, it is still working without it!

Wondering what the major purpose for the SleepEnabler.kextm?


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[ Paul ]Paul **Anonymous** 17 Aug 2011 06:25

Sleepenabler enables sleep, without the proper power management kexts - it's a hack which is specific to the version of OS X.

As for Coolbook I can't get it working on Lion, can't wait until it does! I don't wanna go back to SL. I've tried the hack methods and the XNU-Speedstep kext.

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[ Birdman]BirdmanAnonymous 17 Aug 2011 07:48

Hi! Paul,

Many thanks for the info. For SleepEnabler.kext.

Looking forward to the new and compatible version

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[ Fransisco Miranda]Fransisco MirandaAnonymous 17 Aug 2011 09:49


If you hacked your system following these great instructions to enable CoolBook on Lion, DO NOT INSTALL the 10.7.1 update! (Kernel panic after restart!!!!)

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[ Fransisco Miranda]Fransisco MirandaAnonymous 17 Aug 2011 10:12

Oops, sorry, i can see now that i am not alone… ;)

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JesseJesseAnonymous 17 Aug 2011 21:40

Found an updated SleepEnabler kext for 10.7.1. Can confirm that it works on my Macbook 3,1 (late 2007).

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BirdmanBirdmanAnonymous 17 Aug 2011 22:22

Hi! Jesse,

Can you share with us? where to get it?


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