"System" process is very regularly using all available disk usage.

Pizzanator 20 Reputation points
2026-06-24T08:27:45.4533333+00:00

Lately my computer has been lagging a lot, when I look at task manager, I see that the "System" process is causing my disk usage to spike to 100%. Looking at the properties shows that it's "ntoskrnl.exe".

It happens multiple times a day and can last for minute or so.

I'm using Windows 11 Education, os build 26200.8655.

How can I fix this?

Windows for home | Windows 11 | Performance and system failures
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Answer accepted by question author
DaveM121 930.8K Reputation points Independent Advisor
2026-06-24T09:05:18.6166667+00:00

It depends on what Windows is doing in the background when the disk usage boosts to 100%, it may be scanning your drive for malware, or indexing your files for Windows search.

Click your Start Button, then just type services and press Enter.

In the resulting list of processes, scroll down to find SysMain, then double click that service, stop the service and set its Start-up type to disabled.

Then restart (not shut down) your PC to apply the changes.

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