I had been running PS 12 on an old Windows VISTA box which finally gave up the ghost. Luckily I had done a backup to an external Seagate drive. I bought a new Lenovo B50 Windows 8.1 and loaded up PS 13. While it 'sees' the folders, I'm still getting '?' for some of the 50000 pictures that I have. I've tried running the 'find missing files' and while some have been found, others aren't. Yet under organizer I can see them - I just can't open them. I've tried running a catalog repair but it says that the catalog is fine. Any suggestions would be greatly appreciated.