You will have to speak to your network administrator.
Which may well be you. Don't you just love manuals that say
"contact your network admistrator", I never liked the messages
that read "contact your systems programmer"..
Excel renames a file while working on it then deletes the
original file and renames the new file back to the old filename.
This interferes with networks security permissions that don't like
you renaming and/or deleting files and with AntiVirus programs.
The usual thing is to deactivate the Antivirus program to see if it
works then. If it does contact the AV vendor about Excel usage
with their software.
You can use Save As and give it a different name as a temporary
measure.
Here is a reply by Tom Ogilvy in 2000 with a lot of links you can
check out.
http://google.com/groups?threadm=eqLNu9TYAHA.197@cppssbbsa05
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