I'm about to upgrade to Mountain Lion from Snow Leopard but wanted to see if any of you have run into issues with the mentioned version of Adobe software and the new OS. I usually wait a while for them all to work out any kinks. I figured now would be alright to make the move.
Over at the Adobe forums, the consensus seems to be no real trouble per se with Mountain Lion and versions of Photoshop (CS4) even older than 5 - it's the plug-ins (including some of the older Adobe plugins) you have to worry about.
Besides looking to the websites, you could do a preliminary scan for old PC code: go to the Apple Menu, click on 'About this Mac', and then hit the 'More Info' button. From there click on 'Applications' and look in the right-hand 'Kind' column for anything that shows 'PowerPC' rather than 'Intel' or 'Universal'. PowerPC code won't work in 10.8 - any Power PC apps or plugins will have to be updated. One casualty is the old Photoshop plugin, 'Contact Sheet'. It's PowerPC, and If you've been dragging it forward into newer versions of Photoshop, its career comes to an end with Mountain Lion.
I use Aperture rather than lightroom but have CS5. No problems at all. I have mainly Nik, On One and Topaz. I have not had any issues with any of these. You do need to check for updates.
Problems with CS5 bridge on mountain lion, mac pro 2009. Fixed the permissions but still not 100% stable when opening. Everything else is fine, a little more speedy and love the gestures.