i've heard that there are compatibility issues with LR 3 or 4 and Apple's new OS X Mountain Lion.
could someone clarify this for me please. thanks,
I have a 27 inch iMac with Mountain Lion and am now using LightRoom 4.3RC and have no issues with it at all. Even with ver 4.2, it ran just great. No issues at all. Very happy with it! Can't say enough good about it.