Appreciative wrote:

I do do frequent backups Russ, but the computer on which I have the
problem does not get its contact data via sync. It contains the
master data file and this is synced to the the phone and then synced
to my notebook from the phone. The only file the phone changes is the
notebook and that computer doesn't suffer experience the problem.

It is the "master data file" the is most in need to a good backup scheme. I
make a daily copy of my PST to external storage because it's important
enough to me I want to make sure I'll never lose it.
--
Brian Tillman [MVP-Outlook]