SQL Server 2008 R2 Stuck in Single User Mode
In first run following query in master database exec sp_who If you can’t find the culprit, try SELECT request_session_id FROM sys.dm_tran_locks WHERE resource_database_id = DB_ID(‘YourDatabase’) Then kill all process that use your database with following query: KILL spid Then run following query: USE Master ALTER DATABASE YourDatabase SET MULTI_USER