If reinstalling Office doesn't help, I can't see that upgrading would, either. The fact that you're having extensive problems really does suggest there is a stability issue with your OS X setup or the Office installation itself. Until you resolve those issues, whatever you work on is at risk. Changing applications at this stage is rather like changing horses in the middle of a river ...

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

Just found this thread. I'm empathizing with rachetta. Same story here. Working on a doctoral dissertation using Word for Mac 2011. Last week Word kept crashing every hour or so. This week all my citations disappeared. Very frustrating and disappointing. In my case, upgrading to Office for Mac 2011 won't help because I'm already using that version.

Unlike rachetta, I'm unable to restore the master list for my bibliography. Up until yesterday it was working fine. There were hundreds of items on the list. As of yesterday, there is only one item listed (the last one I entered). No matter how far back I go on Time Machine, when I restore sources.xml I get the same result - only one item on the master list. When I open sources.xml with a text editor it is clearly not empty and the one item that shows up in Word does not appear to be there. Is there any chance that Word is somehow using a different file - something apart from sources.xml?