How to solve SQL Server Error 1222 i.e Unlock a SQL Server table

In the SQL Server Management Studio, to find out details of the active transaction, execute following command.

DBCC opentran()

You will get the detail of the active transaction, then from the SPID of the active transaction, get the detail about the SPID using following commands.

sp_who2 <SPID>
sp_lock <SPID>

For example, if SPID is 69 then execute the command as

sp_who2 69
sp_lock 69

Now , you can kill that process using the following command.

KILL 69

I hope this helps :)