First and foremost, what is a Deadlock? A Deadlock occurs when two or more transactions block each other’s progress because one transaction has a lock on a database object the others need access to. This creates a hard stop on any sort of progress because each process can wait an indefinite amount of time for the locked object. SQL Server steps in to break the stalemate by killing one or more of the blocked process. The unlucky processes that were killed have to start over from scratch.