Why Cumulative Updates May Not Have Installed

Issue

The monthly Cumulative Update for Windows did not install during the scheduled patch policy. Other updates may have been installed, but the Cumulative Update (CU) was missed.

Environment

• Microsoft Windows Server 2019 or below

Cause

The Cumulative Update for Windows patches requires that the latest Servicing Stack Update (SSU) be installed as a prerequisite.

Newer Windows Server versions include the SSU code in the monthly Cumulative Update patches. The requirement to install SSUs is only necessary on Server 2019 and earlier versions.

• Learn - Servicing stack updates 
• Servicing Stack Updates (SSU): Frequently Asked Questions

Windows Update will not show the monthly CU patch as applicable until the latest SSU is installed. This will happen if you are patching with Automox or manually with Windows Update.

Recommendation

Automox recommends creating a policy that installs the Servicing Stack Updates before the primary monthly Windows patching policy runs. This will ensure that the prerequisite patch is installed, which will ensure the main patching policy installs the monthly Cumulative Update.

This policy can be scheduled to run earlier in the day, prior to the policy that targets the Cumulative Updates.

Note: Installing an SSU does not require a reboot, and the device will not flag as pending restart.

Automox has created a template policy that specifically targets the Servicing Stack Updates: Windows - Servicing Stack Updates

Additional Reference

• How Do I Create a Servicing Stack Update Policy?
• Troubleshooting Servicing Stack Updates
• What Are the Recommended Best Practices for Patching in Automox?
• Why Cumulative Updates or Feature Upgrades May Be Blocked by Windows Update Deferrals