Excel error message
 

In Excel 2007, when saving a file, we get the following message...
"Errors were detected while saving FILENAME. Excel may be able to save
the file by removing or repairing some features"

If we click continue, it gives us the file selection screen to "save
as"

Press enter, and we get "The file already exists. Do you want to
replace the existing file?"

If click "yes", the next message is "No errors were detected in
FILENAME. No repairs were necessary"

Click OK and it saves the file.

I have searched newsgroups, but only find references to TrendMicro AV
or MS Livecare possibly causing the problem; neither of which we have.

Any help would be appreciated.