macOS processes › Security and privacy
What is MRT on Mac?
MRT is Apple's Malware Removal Tool, an older part of the built-in malware protection in macOS. Its job of removing known malware has largely moved to XProtect Remediator.
What it does
MRT ran in the background to remove known malware that Apple had added to its definitions. In recent macOS versions that work is done by XProtect's remediation scans, though MRT.app can still be found in /Library/Apple/System/Library/CoreServices.
Why it gets busy
- A background scan, which reads through apps and files.
- Running right after a security update delivered new definitions.
Why is MRT using so much CPU?
If MRT is using CPU, it's scanning for known malware. It finishes on its own, and on current macOS most of this work is done by XProtect.
Is it safe to quit?
It's Apple's protection and exits on its own when the scan is done.
How to calm it down
- Let it finish. Scans end by themselves.
- Keep security updates turned on so protection stays current.
In SystemWatch
SystemWatch explains MRT and XProtect side by side, so you can tell an Apple scan from software you installed.
