SQL server 2012 SP4


ONe of my team have installed SP4 update for SQL server 2012. We are now seeing the below errors

00:01:21 DEBUG: Close the database connection 00:01:21 DEBUG: Open the database connection 00:01:21 DEBUG: BEGIN Connect() 00:01:21 DEBUG: Downgraded SQL connection string 00:01:21 DEBUG: Using ADO provider 'SQLNCLI' 00:01:22 ERROR: Connection.Open: 00:01:22  Error: Invalid connection string attribute 00:01:22  [80004005] Unspecified error 00:01:22  Error: TCP Provider: An existing connection was forcibly closed by the remote host. 00:01:22 00:01:22  [80004005] Unspecified error 00:01:22  Error: Client unable to establish connection 00:01:22  [80004005] Unspecified error

Has anyone run into this?


  • Only when the problem is with SQL Server. Check authentication settings; it may have been set for hybrid (Windows/SQL) and reset to Windows Only when the update was done.
    Also check for firewall settings breaking the connection. The problem will continue until you can successfully connect from the source machine to the SQL server. Use a UDL file to test this.