Final Cut Pro X crashing
Apple have released a recent update to FCPX, 10.2.3 which fixes lots of issues like this. I would recommended this update first as it has solved crashing issues for me.

https://support.apple.com/en-gb/HT201237

Sometimes FCPX doesn't like it when your library is saved separately to user/movies/ perhaps try moving the library there and see if it helps. 

Also media from multiple drives can cause issues if FCP get's stuck trying to link some. If any media is stored on external drives, are they fast drives i.e. thunderbolt, USB3, firewire 800? Potentially FCPX is getting stuck trying to locate the media and can't connect to everything properly. Perhaps try moving media to a reliable drive to try it out like your system drive.

Hope that helps.