Nicko
Perhaps this will apply.
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, 8 Dec 2005 05:55:28 -0600, Nicko
wrote:
Hello Guys,
I have created a (password to open) workbook using Excel 2003 SP1 on a
shared network drive which when I try to save by using Ctrl S or
clicking the Save icon gives me an irritating dialog box which asks:
"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
Please can someone tell me how to deactivate this annoying dialog box
as I have been unsuccesful so far in my efforts 
Many thanks in advance
Nick