We’ve had recurring problems recently with a file server mysteriously losing connection to the network for a few seconds. After going through all of the usual hardware checks, NIC, switch, drivers, etc, we came across this Microsoft NT Debugging Blog entry on kernel file handles. It essentially says to check running processes via Task Manager, Select Columns and add the “Handle Count” column, then sort by it. Anything over 5,000 handles is something to question. We found a process with over 350,000 handles causing our timeout issues. Filed a bug report with the application vendor and the problem disappeared.