Laptop sync on log off

An XP Pro notebook is supposed to synch with mapped drives on a Win2000 server on log off. Syncing at log off worked before SP2 (don’t know that this is or is not the cause, but at least a coincidence). Syncing at log on and periodically works. Syncing at log off results in an error that the mapped drives cannot be found. I assume the network connections are closed before the sync. How to make the log off sync work again?