thxbruce 13 Oct 2011 18:05 in Adobe Acrobat 9.5.2 Pro (for Mac)

I, too, ran into this, but whenever I did, I found that I was trying to skip a 9.1.x or 9.2.x update. That is… I got off of the Adobe site and just kept googling for the next update. e.g.. in your example, I googled for "Adobe Acrobat 9 Pro 9.1.2" That would then give me some links to where I could download that update…. whenever I approach it in this manner, the greyed out .app file turned black and I was able to launch the upgrade. Don't skip even one 9.x.x update and tell me how it goes for you.