Today I was trying to clean up some photos and when the app forced quit and reopened, the Photos app had to rebuild itself. When it did, it opened a library from March. This freaked me out as I thought I lost a few months worth of edited images. While I had a backup from a few weeks ago it was not updated since. My question is, why are there THREE photo libraries?! I know when Photos first came out everyone was making a big deal about having both iPhoto and Photos libraries, but apparently that's fine. But why do I have 2 Photos libraries? And how could the library open from such an old version? I don't keep any backups on my main machine, so I'm not sure where it was getting this information. If anything, it's wasting a ton of usable space!! Any help?