Problem with shared xls file. Could it be blamed on rsync?

[foner-rsync at media.mit.edu]

    Date: Fri, 16 Mar 2007 02:30:33 -0700 (PDT)
    From: syncro <willthatwork at sverige.nu>

    Thanks alot! That's what I wanted to hear ;)
    We want to have an always-up-to-date-copy thus rsync every minute and not
    just at night. However my preventive measure will be a forbiddance of
    sharing xls files or the like.

Rather than forbidding sharing, maybe you could ask rsync (via
files-from and a filter or something) to only back up files haven't
been modified in the last 10 minutes?  I don't know exactly when
Windows might update the file's timestamp vs when data starts getting
written to it---and there will always be a tiny timing race anyway
since the scan of the filesystem and the start of the update aren't
simultaneous---but it might be the file gets backed up every few
minutes when people aren't actively working on it.

The other solution might be to have Windows copy the file to a
temporary location (since Windows might respect its own locks), and
then back up the temporary copy.