Looking for help solving a problem I am having with Solidworks 2016. I deleted a subassembly from another assembly to free up space and when I went back to look at the subassembly, the project would temporarily display for maybe a second and then vanish. It is a relatively large assembly but when I view the file size, it says 200kb which seems too small. Once the project vanishes, a new blank assembly replaces it with no components. I use GrabCad to back up all of my files and when I went in to restore it to a previous state, GC said that the file could not be opened and the reason for this error was unknown. This problem consists weeks back so there are no files that I can restore. I understand that most likely I can not recover the files, although if any of you know how it would be much appreciated, but I would like to know what happened and how I can prevent this in the future. Thanks, any help is appreciated.