MRT high CPU on Mojave

Tj-Shredder wrote:

MRT version 1.68 seems to be unusable not only as others reported on El Capitan and Sierra, also Mojave is affected. It eats more than half of my power, the fan goes crazy and there is no way but removing it! It is supposed to quit after its done its work, but that never happens. Killing it will restart it immediately...

Same as described in uncountable reports already. That is the opposite of security. Apple please fix it fast!

The problem arouse a week ago, should have been fixed already, but isn't...

No there is no point to upgrade to Catalina or higher, as I need my Mac professionally and there are apps I need to rely on which don't run on newer systems...

See if there is anything here

https://eclecticlight.co/2019/07/10/apple-has-pushed-an-update-to-mrt-to-remove-zooms-hidden-web-server/

IMPORTANT NOTE for Sierra and El Capitan users:

There are reports below of MRT 1.68 causing severe problems. You

may wish to avoid updating for the moment, by turning Software Update

off for the time being. If you experience these problems after the

update, try reverting /System/Library/CoreServices/MRT.app to its

previous version, 1.67, from a backup. You’ll need to do that when

booted from a different system, such as an external disk. Please report

any problems to Apple Support so they’re aware of the situation.

It's certainly crashing but the crash report doesn't reveal any actionable information. It usually doesn't.

Two suggestions:

Determine if MRT continues to crash in "Safe Mode": Use safe mode to isolate issues with your Mac

Reinstall macOS: Reinstall macOS - Apple Support

It may be intentional, since Apple had a lot of problems with MRT 1.68 as you wrote. Unfortunately I no longer have any Mojave systems to test.

Maybe MRT was replaced by something bad?

If MRT 1.68 was crashing it would be appropriate for Apple to either fix it or remove it.

An inability to boot Safe Mode is a concern. One of Safe Mode's tasks is to perform a (fairly cursory) startup disk integrity check, and if it's stalling the reason may be that it is "repairing" or attempting to repair some corruption that's taking a long time. You ought to boot Recovery and use Disk Utility's First Aid, and make sure your Time Machine backups (plural) are up to date.

It could be related to MRT's high CPU usage. Lacking additional information regarding the reason version 1.68 appears to have been problematic I'd be very reluctant to even speculate that's the reason.