Hi, I've just installed an SSD on my iMac, installed Yosemite on it and transferred there all my data (apps, documents, settings, etc.) from my old hard drive (which used to be a Mavericks startup partition and now is working as a secondary unit for larger files) What I need to do, first, is to relocate my Aperture Library from Old Disk\Users\User\Pictures, to a new folder in Old Disk\Pictures. What I did was to try opening that file from Photos in Yosemite (which is running in my SSD partition). I confirmed that the app is crap and has nothing to do with Aperture, then I decided to manually move the Aperture file to the main root in my hard drive. What happens next is that if try to open that file with Aperture under Yosemite, it runs the following error: However, if I put the file back in the Old Disk\Users\User\Pictures root, it runs with no problem at all. So the first question is, what's going on, and how can I relocate my Aperture Library? The second question is, how can I delete the rest of folders in my old hard drive (OS, files, etc.)? I tried just selecting everything but my movies and pictures and sending all to the trash, but I discovered that OS X insist in keeping a folder in this path: System\Library\Caches\com.apple.kext.caches\Startup. For me it could be as easy as taking the Aperture Library and my movies, back them up to an external drive and format the old hard disk. However, as I've seen how picky Aperture can get with roots and formats and stuff, I don't want to touch anything yet as I'm risking a total loss of my photos. Thanks for your help.