Log off a disconnected user remotely

First, check the session number with qwinsta:

QWINSTA /server:YOURCOMPUTERNAMEHERE

Write down the session ID.

1. Then use the logoff command:

LOGOFF YOURSESSIONIDHERE /server:YOURCOMPUTERNAMEHERE

Remotely logoff a user by username in one command:

logoff /server:"servername" | qwinsta /server:"servername" "username"