Last Friday, Microsoft released an optional update to the latest version of Windows 10, version 1903 (or an update in May 2019) in the form of a compilation of 18362.329. This patch brought many quality fixes and the release notes did not indicate any known issues, but since then some users have complained about some unusual processor spikes after installing this update.
In two separate Reddit topics noted by Windows Latest, users discuss these problems with high CPU usage, and some identify the underlying Cortana process (SearchUI.exe) as the culprit. For these users, uninstalling the patch seems like the only surefire way to get things back to normal. It is difficult to understand if this is a widespread problem and we do not observe abnormally high CPU usage after installing assembly 18362.329 on one of our computers.
Interestingly, it seems that some Windows Insiders in the Edition Review Ring are giving access to this new optional patch before everyone else noticed that Cortana can cause processor spikes between 30% and 40% in this compilation, even when the digital assistant is not used. Since August, several Feedback Hub items have been sent to this issue, but Microsoft apparently did not act on them, perhaps because they remained buried under many other elements at the Feedback Hub
Microsoft has not yet confirmed this text. possible issues with this optional update, but the reason these optional "C" and "D" patches that Microsoft sends later in the month (after the release of "B" on Patch Tuesday) is because they update the quality of the review. "The intent of these versions is to provide visibility and allow testing of security fixes that will be included in the next version of Tuesday's update," explained Mike Fortin / Corporate Vice President, Windows, in a December 2018 blog post.
we update this post if Microsoft recognizes this problem with high CPU usage in this latest optional patch, but in the meantime, we remind you that you can go back to the previous version if you see unusual CPU spikes in Win Task Manager dows. Keep in mind that optional Windows 10 updates can be frustrating, and it's a good idea to keep them, as any new quality adjustments will eventually be delivered in the next Patch Tuesday update.
Additional reading: Build 18362.239, Cortana, Windows 10, Windows Update May 10, 2019