A session waits on this event when it has requested a mutex for a cursor object in exclusive mode but must wait because it is busy. The mutex is busy because either the mutex is being held in exclusive mode by another session or the mutex is being held shared by one or more sessions. The existing mutex holder(s) must release the mutex before the mutex can be granted exclusively.
Solutions
Solutions for mutex wait problems are very similar to each other.
See Analysis of Waits on Mutexes for more information and troubleshooting ideas.