Windows 10 1903: Buggy update slows PCs, breaks Desktop Search, says Microsoft

Microsoft says a fix for the CPU spiking and search issues is due in mid-September but offers no workarounds.

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Microsoft has finally responded to complaints from some Windows 10 version 1903 users that recent cumulative update KB4512941 is causing CPU usage to surge to between 30% and 40% and in some cases 100%.

As ZDNet reported on Monday, Windows 10 users who installed the update believe the CPU spikes are caused by a problem in the Cortana process SearchUI.exe.

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The issues occurred after installing the KB4512941 update Microsoft released on Friday, August 30, which resolved an issue from an earlier update that broke apps using Visual Basic 6, VBA, and VBScript. 

Microsoft fixed the Visual Basic issue in earlier versions of Windows 10, as well as Windows 7, and Windows 8 in mid-August, promising to fix it in version 1903 by the "end of August". 

It met that timeline. But after testing KB4512941 with Windows Insiders, it also missed a small number of reports of this update causing the CPU issues that 1903 users are now reporting.    

Besides CPU spikes, some users also report that the update breaks Windows Search.

But with the US Labor Day Holiday on Monday, Microsoft may have been caught off guard and only responded to user reports on Wednesday. 

On the known issues page for 1903 and the page for KB4512941, Microsoft has now clarified that the conditions under which CPU spikes occur and Windows Desktop Search fails to return results. 

"Microsoft is getting reports that a small number of users may not receive results when using Windows Desktop Search and may see high CPU usage from SearchUI.exe when searching after installing KB4512941," the company said

"This issue is only encountered on devices in which searching the web from Windows Desktop Search has been disabled."

Microsoft estimates a resolution will be available in mid-September, so it will probably not be fixed by the upcoming Patch Tuesday on September 10, but by a subsequent optional cumulative update. 

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Some users report fixing the issues by editing registry keys, while others report that uninstalling the update resolves the problem. 

However, Microsoft does not offer any workarounds to resolve the issue, suggesting that affected users just sit tight until the middle of the month.  

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