CPU Spike bug in latest Windows 10 1903 update reported to Microsoft
Microsoft released the cumulative update KB4512941 for Windows 10 version 1903 last week; soon thereafter, reports started to emerge on several Internet forums that the update was causing high CPU usage on some systems.
Update: Microsoft confirmed the issue on Twitter via the official Windows Update account.
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.
The official support page for KB4512941 has not been updated yet. It still states "Microsoft is not currently aware of any issues with this update" at the time of writing. End
GÃ¼nter Born was among the first to provide an analysis of the issue. According to the information, it is the Cortana process SearchUI.exe that is causing the load on the system. Windows 10 users can verify that by using Ctrl-Shift-Esc to launch the Task Manager. There they may want to sort the process listing with a click on the CPU header to bring the processes with the highest CPU load to the top of the listing.
Cortana in the Processes tab or SearchUI.exe in the Details tab should be listed there as the culprits on systems affected by the issue. The Start Menu search is not working on affected systems which is a serious issue.
Born suggests that the issue is somehow connected to the cache folder that Cortana uses on Windows 10. An initial workaround had users replace the cache folder with an earlier copy to resolve the issue but most admins would have to uninstall the cumulative update, copy the cache folder before reinstalling it.
According to a user report on Reddit, the issue is experienced on systems on which Bing Search is disabled. Bing Search can be disabled in the Windows Registry or by running one of the many privacy tools for Windows 10.
Microsoft integrated Bing Search natively into Windows 10; users who disliked the integration could turn it off. The company split Cortana and Windows Search in Windows 10 1903, and improved web search in 2017 by adding better previews to the results.
Microsoft has not acknowledged the issue on the official support page for the update. The company pushed the update to the Release Preview ring and some testers have reported the issue during that phase to Microsoft. The reports did not receive many votes however and it seems likely that Microsoft did not prioritize the bug because of that.
A solution is making the rounds that fixed the issue on some devices reportedly. Admins would have to enable Bing Search -- the sending of local search queries to Microsoft's Bing search engine, to fix the issue for the time being. Here is how that is done:
- Use Windows-R to bring up the run box.
- Type regedit.exe and hit the Enter-key.
- Confirm the UAC prompt.
- Go to Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Search
- Right-click on Search and select Export from the context menu to back up the data.
- Locate the Dword value BingSearchEnabled.
- Either delete the key, or set it to 1.
- Restart the PC.
Another option is to uninstall the cumulative update to go back to the previous version.
The incident is not the first on Windows 10. Microsoft broke the option to disable web searching in Windows 10 1803.
It is unclear at this point how widespread the issue is. Microsoft has not acknowledged it and while it has made the rounds on forums and tech blogs, it seems to affect systems with Bing Search turned off only.
Now You: is Microsoft doing enough bug testing?
Invasive crap no one asked for is causing problems?! Absolutely shocking! Shocking I say! No one could’ve seen this coming! No one!
Indeed. It simply can’t be true. ;-)
This situation reminds me of that time Microsoft got in trouble with the US for using their monopoly on the desktop to push their other products, thereby harming both competition and consumers.
Justice is apparently alive and well.
Rather than re-enabling Bing or uninstalling the update, I just removed all the files within the cache folders (need to takeown then icacl them all first) and rebooted. But the issue went away on the only affected machine I had.
I don’t even use Cortana let alone leave it to use Bing.
When using sfc /scannow the problem is reactivated
Probably most machines at Microsoft are running Server 1809 and LTSC 1809. Nobody cares about releases such as 1903, 1803, 170x or 1511.
There is no Dword value BingSearch on my computer. (Dutch language).
It is BingSearchEnabled. Did you noticed the CPU spike issue?
No BingSearchEnabled entry on my computer with Windows 10 Home. I did not install KB4512941, due to all the problems reported.
However last week my CPU usage skyrocketed, after I removed old Windows updates with Windows disk cleanup. This problem has been described on another forum, I forgot which one.
It has something to do with a new way MS installs updates, that’s all I remember for the moment.
anyway I restored my computer with a Macrium image. That fixed the high CPU usage. I have postponed updates to 21 September and will not touch Disk cleanup nor sfc /scannow.
Disable Web Search.reg
Windows Registry Editor Version 5.00
Missed one …
I have Bing enabled and installed the update. Haven’t seen any cpu spike yet
I installed the update yesterday although I was not sure about whether I would be getting any crazy stuff happening on my pc. So far nothing. It looks like this affects just a bunch of people who disabled bing search. I never did and did not even bother .
So the update works for me – for the dozen or so people who have the problem, uninstall the update guys. It is not something so dramatic. Uninstall it and WAIT for the correct update.
Thank you so much Martin ! Deleting that piece of sh… registry key “BingSearchEnabled” and restarting worked for me.
If I hadn’t read your website this morning I would have been clueless facing this problem… what a shame on Microsoft, I have no words for their lack of quality and respect for their clients…
According to https://www.howtogeek.com/224159/how-to-disable-bing-in-the-windows-10-start-menu/ you have to create the BingSearchEnabled entry yourself.
I am running Windows 10 Pro 1903 18362.329 which is the 4512941 update on a modern custom built computer. I never really have to worry about problems with MS Updates as I always have an Image of my Hard Drive to fall back on if disaster strikes.
NO I do not think MS is doing enough quality Testing. It is hard to believe that with all
the Fast Ring Beta testers out there that they did not come across this problem before MS gave it the green light.
I noticed this problem yesterday in my Task Manager, but Cortana only used about 20% CPU. I use Classic shell & SearchUI is blocked from accessing the Internet, I am also using
O&O ShutUp10 TinyWall 2.1.12. & FireFox. No Bing search for me.
Here is what worked for me…
I ran the Task Manager as an Administrator & under Processes I Right Clicked on Cortana & Selected End Task. When I first did this a couple of times a Green Symbol appeared & it says suspended to improve performance. I clicked on it few more times & now Cortana is completely gone from the list & my CPU is back to normal.
Here is what does not make any sense to me… I have Cortana Disabled in The Group Policy Editor. I am so sick & tired of MS not giving control to the user, especially when it comes to Windows 10 PRO I am the Administrator, its my computer not yours MS. There is no excuse for this. A Simple example… In GPE I have Windows Updates set to Notify only & let me choose to Download Updates but MS does not respect this because here is what it says in Windows Update screen… We’ll ask you to download Updates, Except when updates are required to keep Windows running smoothly,In that case we’ll automatically download those updates.
What a joke. I prefer to download the update using the Windows Update Catalog because for me it;s a lot faster than using windows update. I want control over my system so for Pro & Enterprise users MS keep your incompetent hands off my machine.
I had cortana and bing search disabled and by activating both again, the problem is gone for me.
I disabled SearchUI completely by creating restriction policy from secpol. I use “Everything” as a search indexer anyway, no need to waste resources.
Thank you very much. Problem is gone
Windows 10 is like a box of chocolates, you never know what your going to get.
I’ve disabled that crap process entirely as the mentioned workaround didn’t work for me.
mockroot wrote: “I disabled SearchUI completely by creating restriction policy from secpol.”
Good idea. Thanks for the suggestion.
I was getting 60 degrees celsius off of my CPU. Not even games can manage to bring the temperature that high. I re-enabled Bing Search and problem solved for now. When the fix will be available, Bing and Cortana is gone again.
Microsoft is slowly killing Windows so that the home user stops using it. The truth is that we use an outdated and archaic system that does not match current technological developments. Windows is an 80’s system that has undergone few changes in 30 years, it should not be used today. I look forward to a quantum physics-based operating system, but I think it will take a few decades to come.
This script did the trick:
I suppose running sfc /scannow will cause the problem to come back, though. But it’s real easy to just force the script to run again after that so, it is a viable workaround until M$ provides a permanent fixâ”€here’s hoping they’ll do that within the next 5 years. lol :-P
Nobody mentioned the Printers & scanners dialog is also borked after 1903 – standard users can’t click the Open queue and Manage buttons. Seriously, at least some testing before release would be useful.
You’re the best Martin. You saved me a whole lotta grief. I read the article and checked to see if this update was installed, and sure enough, it was on board ready to be downloaded and installed. I paused updates till around mid month. I am however not sure how to monitor if and when it’s fixed. Will the KB# change?
Microsoft has not acknowledged the bug official; if the company does not, you won’t know about it as it won’t make any reference to it.
Ah. Thanks for that. Guess I’ll just wait till mid month and hope it’s rectified by then.
ghacks has seriously been my go to in regards to helping educate myself, and keeping up to date with software. I always look forward to your newsletter!
I did the Secpol solution as well…Good tip. I did a Reboot & now Cortana is gone from the Task Manager & my CPU is Normal.
For those people on the Windows 10 Home Edition you can easily upgrade it to the
Pro version for about $99.00. Even if you are not too familiar with computers etc. You can get
step by step instructions on anything you do not know by doing a Google Search.
Here is an example when doing a Google search for How to Disable SearchUI using Secpol.
I applied the same concept, by using Kasprsky’s application control/firewall function to completely disable Cotana’s “SearchUI.exe”. However, thank you for the information regarding Secpol option. I will try this as well.
@CTK said on September 3, 2019 at 4:20 pm
For those people on the Windows 10 Home Edition you can easily upgrade it to the Pro version for about $99.00.For those people on the Windows 10 Home Edition you can easily upgrade it to the Pro version for about $99.00.
Manufacturers’ PCs (Dell, etc.) cannot upgrade the OS due to a compensation contract.
I’m the “Home” user, but I’m blocking updates with “WPD”.
Windows 10 Home (x64) Version 1903 (build 18362.295)
I have this issue. Cant uninstall the update fails every time amazing. Just “upgraded” to Windows 10 due to a hardware upgrade after staying on 8.1 for years wish I could go back.
MS has acknowledged the issue on Twitter: 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.
and MS has updated support article 4512941 this Wednesday Sept. 4 to acknowledge the problem AND estimates a solution will be available in mid-September:
And has adapted the support page for KB4512941: see “Known issues with this update” on https://support.microsoft.com/en-us/help/4512941/windows-10-update-kb4512941.
“We are working on a resolution and estimate a solution will be available in mid-September.”