Endnote X8 keeps crashing. Unable to recover groups, lose PDF attachments every time

I’m working with an initial library of 776 refs, sorted into 4 groups.  My core library (one of these groups) is ~130 papers, PDFs attached, to be used in Word.  I haven’t got to Word yet - every few hours Endnote crashes and I lose all my groups and the PDFs drop off, so I have been unable to actually test the library with any Word document so far. 

Help??

I haven’t moved any files since opening the library, haven’t renamed anything, haven’t touched the DATA file.  The library is only saved on my computer and I’m working directly off it.  When it crashes, upon reopening I see a file with all 776 refs and only 2 groups.  I have no idea why it’s reverting to this earlier file type and can’t recover anything with all my groups and PDFs, it seems to have dropped off my computer completely.