Microsoft today pushed Windows 10 Build 17134.285 (10.0.17134.285) as cumulative update KB4457128 to those on the latest April 2018 update or on Windows 10 version 1803. This update addresses an issue that causes the Program Compatibility Assistant (PCA) service to have excessive CPU usage. This occurs when the concurrency of two simultaneous add and remove programs (ARP) monitoring threads is not handled correctly.

The changelog for the Build 17134.285 mentions many more fixes, improvements, and security updates.

Windows 10 Build 17134.285 Changelog:

Improvements and fixes


This update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:

  • Provides protection against a Spectre Variant 2 vulnerability (CVE-2017-5715) for ARM64 devices.
  • Addresses an issue that causes the Program Compatibility Assistant (PCA) service to have excessive CPU usage. This occurs when the concurrency of two simultaneous add and remove programs (ARP) monitoring threads is not handled correctly.
  • Security updates to Internet Explorer, Microsoft Edge, Microsoft scripting engine, Microsoft Graphics Component, Windows media, Windows Shell, Windows Hyper-V, Windows datacenter networking, Windows virtualization and kernel, Windows Linux, Windows kernel, Microsoft JET Database Engine, Windows MSXML, and Windows Server.

If you installed earlier updates, only the new fixes in this package will be downloaded and installed on your device.