External Cell reference changing on its own within a SharePoint

[jwahl16]

I have excel 2010 and I think SharePoint 2007. On the sharepoint, there are 7 workbooks hosted. 1 workbook references and pulls data from the other 6. The other 6 workbooks are periodically checked out, updated, and checked back in. All was working fine but now the main workbook is referencing a users C drive instead of the location within the SharePoint. So of course this prevents the workbook from updating. The formula cells are even locked so I don't think it's possible someone changed them. Is this just SharePoint and Excel not playing nice with each other? How can i prevent the cell reference from changing like that?

TIA!

[jwahl16]

Ok so I think I've narrowed it down a little bit.

If i don't have the other files open, the data won't update, but the links will remain intact. So in order to actually update the content the files must open (I use a VB script because they are password protected) but the links will change to my home directory instead of the SharePoints. I'm new to SharePoint so this is quite puzzling. I hope to read your responses soon!

[jwahl16]

One more update:

I can recreate the issue by checking 'use my local drafts folder.' The person who caused this issue said they did not do this though. Is it possible it did this through some other default setting?

Sorry for being all over the place with my questions