Endnote LOSES references in my library

I have noticed on two occasions now that when i close MS word 2007 and reopen it and endnote that several refernces that were previosly imported into it are gone.  WHen you unformat and reformat, it cannot find them.  How do I solve this???  Im trying to write a thesis and really can’t have this kind of instability…

Is this something I caused?

Endnote X3, windows 7, ms office 7

I am also having a problem losing references from my library. My library is large and I use it primarily to generate annotated bibliographies. This is the second time I have had it drop over 100 references. Anyone else having this problem or am I doing something wrong.

EndNote X1, Windows Vista

Although the developers have tried very hard not to allow it, there are specific ways to circumvent their work, and end up with the accidental insertion of a citation taken from the online database rather than first copying it to your library and inserting the endnote citation from there.  One of my colleagues managed it, when I thought it wasn’t possible, and then demonstrated it to me.  

Perhaps you found the way too, which I won’t describe, because you shouldn’t do it!