I had an issue with Photoshop and Lightroom a few years ago(maybe CS4 and LR 2?). I had the physical discs and they would not install on my MBP. I tried loading them on a friends iMac and they wouldn't load there, either. I DL'd from Adobe and used my activation keys that came with the discs and all was well. It was strange, because I believe I was able to install LR on Parallels/Windows 7 with the disc.