System restart cannot be completed while another software installation is in progress. Please allow the software installation to complete before attempting a system restart

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User gets an error prompt “A system restart cannot be completed while another software installation is in progress. Please allow the software installation to complete before attempting a system restart.”
 
Cause:
Under very specific conditions, the persistent job counter is not decremented when a job is finished. The coordinating system prevents these client computers from being restarted because it believes that a job is still running based on the JobCounter value.
Solution:
1.     Stop the SMS Agent Host (CcmExec.exe) service on a System Center Configuration Manager 2007 SP1 client computer.
2.     Location the following registry subkey and change its value to 0:
HKEY_LOCAL_MACHINESoftwareMicrosoftSmsMobile ClientReboot ManagementJobCounter
3.     Start the SMS Agent Host (ccmExec.exe) service on the client computer.