Looking at the compliance reports I see that most of updates are installing ok but some are constantly saying “Waiting for another installation to complete”

The updates won’t install and end-users are constantly getting an error saying the another installation process is already running. It’s not another running process causing the problem, so restarting services won’t help. Information is stored in WMI and most likely is caused by an earlier installation that failed.

To fix the problem

1. Log on to the client and stop the Windows Management Instrumentation Service – WMI
   
   
   
2. Rename the Repository folder to RepositoryOLD. The folder is found  in %systemroot%\system32\WBEM
   
   
   
3. Restart the Windows Management Instrumentation Service. This will create a new Repository folder and the software update installation will be able to start.