Windows 10 KB4512941 causes high CPU usage by Cortana [UPDATED: Microsoft is working on it]
Following the release of KB4512941 for Windows 10 version 1903, users have noticed a huge leap in CPU usage by Cortana.
After installing the cumulative update, the Cortana process SearchUI.exe is making much higher use of the CPU for many people. The problem can arise on systems where Bing Search has been disabled, and a series of workarounds have been suggested while Microsoft works on addressing the problem.
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Complaints about high CPU usage started to appear on Reddit over the weekend, with some users also experiencing issues with blank Windows Search results. Despite the number of reports from users who have installed the update, Microsoft is yet to acknowledge that there is a problem -- as such, it is difficult to say when the issue will be addressed.
In all, a total of three workarounds have been unearthed. The first is to simply uninstall KB4512941, but as the update addresses a number of other issues, this is probably not the best idea. Another option is, as suggested by Günter Born, to replace Cortana's cache folder with an older version -- but this is something of a hassle.
Perhaps the best option for now is to simple ensure that Bing Search is enabled. You can do this using the following steps:
- Launch the Registry Editor by pressing the Windows key and R, typing regedit and pressing Enter.
- Navigate to HKEY_CURRENT_USER\Software\Microsoft\ Windows\CurrentVersion\Search
- Find the DWORD value called BingSearchEnabled and either delete it, or set its value to 1.
Microsoft has now acknowledged the problem and is working on a fix that will be made available in a future release:
We are currently investigating an issue where users are reporting high CPU usage linked to SeachUI.EXE after installing the optional update on August 30 (KB4512941). We will provide an update in an upcoming release.
— Windows Update (@WindowsUpdate) September 3, 2019