This one is giving me grief! On my network I have 2 systems (Prime & Cube) Cube connects direct to the router. Prime (we have a geography problem!) through a 3COM switch. If I connect Cube to the router I get this in the event viewer (see att). There is no network traffic and attempts to find the other system show nothing and often lock up explorer. Both systems running XP Pro SPII and up to date on updates. Both systems run F-Secure internet security although disabling it does not make any difference. All NICs set to get IP addresses automatically. A WAN ping works but not on the LAN. This only effects the LAN - access to the internet is not affected. Reference to the MS site shows nothing and I find that MRxSmb is supposed to be a file storing network data. Searching the system for it shows it doesn't change with each reboot so maybe that isn't correct. Anybody any ideas what is going on here?