Automatic Name Checking Does Not Work

Recently we had a server crash, and had to reinstall SBS2000 and
Exchange 2000. We restored the mailboxes from tape and all users seem
to be able to use mail fine with just 2-3 exceptions (out of 40)...

The biggest problem I have now is that I have 2 users (one using Outlook
2k and the other Outlook 2k2) which Automatic Name Checking (ANC)
doesn't seem to work for.

- The contacts to which it isn't working for are the Contacts folder
for the user and the Firm Contacts shared contacts folder. The Global
Address list works perfectly.

- ANC is enabled under OptionsEmail OptionsAdvanced E-mail Options

- Both Contacts and Firm Contacts are set to Show this folder as an
E-mail address book.

- We have tried deleting the .nick files thinking they were corrupt,
but it didn't help.

- We deleted the old mail profile and created a new one, which didn't
help.

- We added a mail profile but that didn't help either.

HELP! This is such a minor thing but such a huge annoyance.