I setup Outlook 2003 in cached Exchange mode on a new laptop and tried to synchronize a mailbox with a couple thousand messages in it. The synchronization would synch a few messages and then fail. Synchronization errors indicated that the messages were being scanned by an antivirus program. I disabled XMON on the Exchange server and Outlook completed a long synchronization. Has anyone else run into this? I used to have a problem like this with another vendor's Exchange scanner until I reconfigured it to run the signature updates at night and ran the background scan before morning.