Microsoft has acknowledged an issue with Windows 10 1903’s latest cumulative updates that’s causing high CPU usage. The problem, which appears to originate in Cortana’s SearchUI.exe, was first reported on the Feedback Hub before its release, then again around a week ago.
The tech giant is working on a fix for the problem, which it believes effects a “small number of users”. It has an estimated release of mid-September for the patch and is yet to post an official workaround.
However, users on Reddit have previously shared several imperfect solutions to the problem. The most foolproof way is to uninstall KB451294. You can do this via the ‘Uninstall updates’ option under ‘View update history’. You’ll be losing fixes for spatial audio, Remote Desktop, and more, but it could be worth it.
Registry Tweaks and Cache Replacements
If you want to keep the fixes without rolling back, reports suggest registry tweaks are the way to go. Obviously, fiddling around in the registry can cause issues if you aren’t careful, so be sure to make a backup.
Press Windows+R and type regedit.exe. In the search bar, navigate to ‘Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Search’. You can set the Reg Value for BingSearchEnabled 0. Delete the key, but be aware this will mean all local search queries are sent to Bing.
Instead, you may have luck replacing your Cortana cache with one from an older build. User falcon4fun from the Windows Ten forums has shared his from 362.295. You can replace the one in ‘C:\Windows\SystemApps\Microsoft.Windows.Cortana_cw5n1h2txyewy\cache\’ with his.
These temporary workarounds should help users until Microsoft solves the root cause in a week or so. Of course, while the relatively speedy fix is appreciated, it would have been nicer if the company listened to the reports of its insiders and fixed it before release.