Microsoft: We've fixed Windows 10 1903's Cortana CPU spike bug

Microsoft's mega Patch Tuesday update also brought a fix for a several-week-old Cortana bug that was causing high CPU pain for Windows 10 version 1903 users. 

Microsoft last week finally acknowledged user complaints about the Cortana process SearchUI.exe causing abnormally high CPU usage. 

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Complaints rolled in after users installed the KB4512941 update that Microsoft released on Friday, August 30, to address bugs from a previous cumulative update that were lingering on in version 1903. 

Microsoft promised that a fix for the high CPU usage would be provided by mid-September, but the company actually delivered it a little earlier, as part of its huge September Patch Tuesday update. 

"Addresses an issue that causes high CPU usage from SearchUI.exe for a small number of users. This issue only occurs on devices that have disabled searching the web using Windows Desktop Search," Microsoft said in the security update KB4515384 released yesterday. 

Still, a small number of Windows Insiders had reported the same issue through the Feedback Hub in preview testing of the buggy update, which Microsoft missed despite recent efforts to improve its detection of narrowly reported issues  

The Patch Tuesday update address two zero-day elevation of privilege flaws that were under attack already. The update included 80 security fixes.   

Additionally, Microsoft patched two remote code execution bugs in the Remote Desktop Protocol. However, these don't appear to be as dangerous as the recent BlueKeep and DejaBlue vulnerabilities, which could be used to create a wormable exploit to automatically infect vulnerable machines on the same network.

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

"Unlike BlueKeep and DejaBlue, these members of the Blue Bug Group are all client-side. An attacker would need to convince someone to connect to their malicious RDP server or otherwise intercept (MITM) the traffic," said Dustin Childs from Trend Micro's Zero Day Initiative.  

"It's good to see these issues patched, but they don't carry the urgency of the recent wormable bugs."

More on Microsoft's Windows 10 updates

• Windows 10 1903: Buggy update slows PCs, breaks Desktop Search, says 
• Windows 10 CPU spikes? 1903 update brings fixes but also high usage issues
• Windows 10: We're now gearing up for 1909 with new throttled release, says Microsoft
• Microsoft: These Windows 10 updates fix broken Visual Basic apps but not for 1903
• Microsoft warns Windows 10 admins: No more patches for 1703 after October 9
• No more buggy Windows 10 updates? Microsoft makes it easier to flag early flaws
  
• Windows 10 recovery: Microsoft borrows Apple's Mac cloud reinstall feature
  
• Microsoft releases two new Windows 10 19H2 test builds
• A new look for Windows 10 Start menu: Live Tiles ditched in leaked preview build
• Windows 10 19H2: If you're on 1903, expect 'far faster' update, says Microsoft
• Microsoft starts testing Windows 10 19H2 in the Slow Ring
• Windows 10 updates: We're now using AI to push 1803 users to 1903, says Microsoft
• Windows 10 yields more secrets: Microsoft plan to split OS from shell takes shape
• How to delete the Windows 10 paging file on every shut-down TechRepublic
• Test Microsoft's Chrome-like Edge browser for Windows 10 CNET