Discrepancy in patches to be installed for same OS machines.

Products

• CA Client Automation - IT Client Manager
• CA Client Automation - Patch Manager

Issue/Introduction

We have servers running same OS (Windows) which are patched periodically using Patch Manager. We have noticed that the number of patches required to be installed has never been the same although they have the same operating system and are always patched together.

What causes this behavior? 

Environment

Release : All supported versions.

Resolution

Patch Me intellirollup includes enhanced patch applicability logic by utilizing Windows Update Agent API. It's not required to have the same patches for both the machines, although they have the same OS. It depends on the Roles and features configured on the server and version of .Net application staged etc., based on those no. of patches required for the machine will change.