Surface Pro 4: High CPU load from Service Host "Locale System"

[German]Some users are facing a mysterious issue in Windows 10; The Service Host “Locale System” (SVChost) is causing suddenly a high CPU load and the fan spins continuously.


A blog reader has pointed me to this issue. So I decided, to post this case here, in the hope, that it may help others. The blog reader wrote:

One of my customers run into trouble with a Surface Pro 4 (i7/16GB RAM / 256GB SSD). The Service Host “Locale System” is causing 33-40% CPU load and the fan spins continuously. The SP4 is just 6 months old.

I found out, that the service wuauserv is causing this issue. But I can’t stop this service via Task Manager. The service also downloads Window Defender signature files, but stops at 89% and starts again with the download

I’ve stopped the service (I killed SVChost in Task Manager). Then I was able to stop Windows Update. Afterward the CPU loads goes down to 2%-25%. 

He mentioned, that searching the web didn’t come with an explanation at all. I supposed a damaged Windows Update store.

The solution for this issue

A few days later, the blog reader came back with an explanation for this behavior. He wrote in another e-mail:

I was able to find the root cause and a solution for this behavior. I’ve set the network as a ‘metered connection’ to avoid updates via a mobile device router. Then I let Windows Update search for updates. Windows Update found a definition update for Windows Defender, but did not download it, due to the metered connection.

But my user decided to download this Defender signature update, but wasn’t aware, that his LTE router has just an EDGE connection. So the download took hours. He shut down his Surface Pro 4 before the download has been finished. At home he connected to a Wi-Fi network and the suspended download was revoked. It seems that Windows Update service failed at this point and was only able to download the signature file up to 89%. The the download stops and restarts with 0 % again and again. 

Killing the SVChost process in Task Manager solved this issue (I tried it with a Wi-Fi connection). Then I downloaded the Defender signature update via Wi-Fi. Now the Windows Update service can be stopped and started in a regular base. And the CPU load is down to 1%. Also the battery lasts for a long time. 

It’s a curious root cause for this issue, so I thought, I documented it within my blog. My thanks to to Blog reader Michael G. for his information. Maybe it helps others in a similar case.


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