Problem

Caused by client not being able to see the Offline Address Book.

1. Log onto the Exchange Server.
2. Start > All Programs > Exchange Management Console > Organisation Configuration > Mailbox > Offline address Book > Create a new one (Must have a different name to {Default}.
3. Delete the Old Offline Address Book.
4. Set the one you created as the default.

WAIT 20 MINUTES – If the Problem Persists

1. Log onto the Exchange Server.
2. Start > All Programs > Exchange Management Console > Server Configuration > Mailbox.
3. Select the Mailbox store in the middle section > Right Click > Properties.
4. Client Settings tab > Browse > Select the Address book you created above > OK > OK.

WAIT 20 MINUTES

Note: I’ve also fixed by creating a new mail profile - though when I switched back to the original one it was ok - so I may not have been patient enough.

MS KB 905813

MS KB 411331