Symptoms
Assume that you use Microsoft SQL Server 2012 or SQL Server 2014. When you run a query to update a table that has an XML calculated column, an access violation exception occurs. The query works correctly after you drop the constraints of the table. An access violation occurs again when you try to re-add the constraints. You receive the following error:
A severe error occurred on the current command. The results, if any, should be discarded.
Cause
An internal metadata object is reset incorrectly. This leads to the exception.
Resolution
The issue was first fixed in the following cumulative update of SQL Server.
Cumulative Update 1 for SQL Server 2014 /en-us/help/2931693
Cumulative Update 9 for SQL Server 2012 SP1 /en-us/help/2931078
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.