By skyforbes 
Follow below solution steps to resolve Windows update error due to update service was shutting down.
Problem: Windows users encounter a Windows update error stating “We could not complete the installation because an update service was shutting down” when updating Windows to the newer version, causing unable to proceed further for Windows update installation.
The detail error message as below:
Windows Update Error
We Could not Complete the Install Because an Update Service Was Shutting Down
Follow below solution steps to resolve Windows update error due to update service was shutting down.
Content Summary
Potential Causes
Solution 1: Correct Date and Time Settings
Solution 2: Restart Windows Update Services
Solution 3: Uninstall Antivirus Software
Solution 4: Execute Windows Update Troubleshooter
Solution 5: Repair Corrupted Windows Update Database
Solution 6: Repair Corrupted Windows Files
Solution 7: Execute Complete Windows Update Failed Troubleshooting Steps
Reference