corrupted source list?

[bkcell]

i am working on a 190k word (so far) document with 137 citations. at some point it becomes impossible to update the source list. after laboring for .5hr or so it crashes Word. I've uninstalled and reinstalled both Word 2007 and 2013. I could probably recover an older version of the file before this problem but then would have to figure out to merge the new data into it, maybe doable, maybe not. if i can't fix this i'll have to freeze the existing source structure (convert to static text) then manage sources manually until completion. any suggestions greatly appreciated.