I have a desktop that I was using as my primary computer for 6 months. Due to software issues I had to delete all content. I made backups.
I am now away from my office with the backup drive for the desktop and a comparatively small laptop (my mac air has 128GB, the desktop has 3TB) but find myself needing to sort through old photos for insurance purposes however the app refuses to load the photos library from the backup disk.
Furthermore, before getting the desktop, I stored all photos in an "external iPhotos library" and this library will also not open. This is new to me as of the update to Yosemite.
Any assistance would be greatly appreciated: anything is better than browsing masters one folder at a time!
All the best,
RA