Antimalware Service Executable Causing High CPU Usage

Hi everyone,

I’ve been having an ongoing issue with Antimalware Service Executable (MsMpEng.exe) using very high CPU (sometimes 60–90%) on my Windows PC. This causes serious slowdowns, lag, and occasionally freezes, especially during startup or while working with files.

I’ve already tried basic steps like updating Windows, running a full scan, and checking for malware, but the problem keeps coming back.

My main concerns are:

How can I reduce or stop the high CPU usage without disabling Windows Defender completely?

Could this issue affect or corrupt my files over time due to system freezes or forced shutdowns?

This topic was modified 6 days, 7 hours ago by Sofia.

Tagged: Windows 11

Windows data recovery

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Mira Lennox Lennox

Participant

January 9, 2026 at 10:28 am

Set a CPU usage limit for Microsoft Defender and reschedule its scans. In Windows 11 you can limit how much CPU Defender is allowed to use during scans so it stays active without overwhelming your system, especially at startup. You can also change scan timing so it runs when the PC is idle instead of while you’re working with files. High CPU usage alone won’t damage data, but repeated freezes and forced shutdowns can cause file corruption over time, so reducing those spikes is important to protect your files.

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