I have several clients experiencing the same following problem, with most of the system details similar. The problem is when their PC has Offline Files enabled and one or more folders set to synchronize, the user's network connectivity repeatedly disconnects them from the Windows 2003 Server. Disconnection frequency is about every 5 - 15 minutes. If the user forces synchronization, they are reconnected immediately after synchronization completes. All clients are XP Pro SP2, connected to domain controller (one) via CAT-5e cable or 802.11g wireless network. Each case there is only one subnet, domain controller acts as AD, DHCP, DNS. Turning off Offline Files resolves problem. All clients are fully patched (AutomaticUpdates is on, WU run manually to ensure) and W2003Svr is fully patched.