Have a look at this KB Article

"The file may have been changed..." error when you save work*book to network
server in Excel 2002

http://support.microsoft.com/default.aspx?kbid=324491

Myrna Larson also reported that she got this error when opening a workspace
(*.xlw) file.

Opening the workbooks individually solved the problem.


Gord Dibben Excel MVP

On Thu, 31 Mar 2005 11:00:44 -0800, "jlbreyer"
wrote:

On several, but not all, workbooks, when I save I get a
box up with the message:

"The file 'filename.xls' may have been changed by another
user since you last saved it. In that case, what do you
want to do? ()Save a copy () Overwrite changes."

Tried searching the knowledge base with no luck. Has
anyone else seen this? Do you have a cure?

jlb