SCCM 2012 - Unable to delete application or edit task sequence

A few days ago I experienced something unusual where I was unable to delete any applications or edit a task sequence.

I have seen some posts where they recommend to query the SCCM database to check if something is locked and if it is then delete the row. This is not supported and it didn't work for me but I will post here just for the sake of completeness.

Open the SQL Server Management Studio and browse to the SCCM database.
Click on New Query.

Type the following and click on Execute:

Now if you have something locked it should show up. Get the ID of the locked object and replace it in the command below. Click on Execute.

OK now to the solution that worked for me.

Just restart the WMI service or alternatively restart the server.

net stop winmgmt && net start winmgmt