Bad situation. I am having the same issue. Called Tech Support: the tech performed a quick scan but apparently has no clue about the cause. It just occurred again: while editing photo files the PC performed a spurious reboot which resulted in the MMSH service to start up (>60% CPU). I am now suspecting that McAfee is the cause of the unwanted reboot since it had occurred before.
NEED ACTION ASAP!!!!!
That link I posted McAfee is wanting at least another user with the issue to get logs of teh issue happening and send them to Mcafee. If interest post there and Macfee tech will contact you to show what you need to get the logs. They will be big so you will either need a dropbox account or ftp them to McAfee.
Placed another call to the Help desk. After several futile tests (quick clean, quick scan, system restart) the technician recommended uninstalling and reinstalling the app. I did this and the McAfee app is running normally for the moment.
And so far, I can again mention that the issue has not yet re-appeared since I launched the McAfee tool provided to me by one of their Tech.. I monitor constantly the running processes with "Process Hacker 2" and it does not show anymore within the 20 apps running and using large CPU usage. That's for about the third week by now! (Refer to my previous posts above)
Same issue with me. CPU usage typically above 80% and as high as 92%. It has taken a while to get this posted as even my mouse hangs motionless every minute or so. This is rubbish. Looks like I will need to disable or remove McAfee if I am to get anything done today, as I'm not able to end the task in Task Manager. Any help greatly appreciated!
As I mentioned this issue is only so far being reported by 12 users out of well a lot more. We mods have not seen it on our PCs nor have the techs on their test pCs. Nevertheless we have arranged for support to get 3 users to take logs before and during the issue occurring to see what is causing this. Hopefully this test will happen soon.