Fix: Unknown SQL Exception 10054 Occurred.

You may receive an error message in Windows Event log that prevents SQL database connections form being made and causes the SQL database application to be offline.

Unknown SQL Exception 10054 occurred. Additional error information from SQL Server is included below.

A connection was successfully established with the server. But then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)

1. Check to see if Network Interface teaming (NIC teaming) is enabled on the SQL server network interface, as NIC teaming could be causing this error.

2. The errors may be generated from recent Microsoft security patches (including KB948496) installed. Revert any patches that were recently installed on the SQL server.