Descriptor for system table '%Id' in database '%d' not found in the descriptor hash table.
This error indicates that the in-memory structure used by SQL Server to access a system table has been reused. Usually, only user-table descriptors are reused; system table descriptors are always in memory.
Shut down and restart SQL Server. Upon restarting, run DBCC CHECKDB, DBCC NEWALLOC, and DBCC CHECKCATALOG to verify that there are no structural problems in the database that may have led to this error.
Because the problem is with the in-memory structures, shutting down and restarting SQL Server will usually resolve the problem. If the problem persists contact your primary support provider. Have the full output from the DBCC CHECKDB, DBCC NEWALLOC, and DBCC CHECKCATALOG available for review.