I've only very recently able to narrow this down as some of the XBOX game pass games were not able to run after install. Here's what happens
1. Install game on XBOX game pass
2. Try to run game, nothing happens, system becomes sluggish.
3. Task Manager shows MBAM eating up 30-40% CPU
4. Game Process itself at 0% CPU seemingly unable to run
I had assumed MBAM was just running scheduled scans and didn't think much of it and attributed it to old games that I was running having some issues with Win 11. However yesterday I installed Iron Harvest and was not able to get it to initiate even though the process shows up in Task Manager, its just stuck there and MBAM was at a constant 30%. I then realised it might be MBAM causing the issue because the scheduled scan just completed 5 mins ago as I got the notification so there was no way MBAM was running scans again. Since restarting MBAM service doesn't work or at least I can't do it anymore in Task Manager or Services, I disabled all real time protections and rebooted my system. lo and behold, Iron Harvest loaded, MBAM was at normal CPU utilisation. Closed Iron Harvest, rebooted with all real-time protections turned on, loaded Iron Harvest, same issue, MBAM CPU Utilisation shot up and stayed up, Iron Harvest process was running but not loading the game.
I've since added Iron Harvest to the exclusion list however since I've had older games with the same issues before I figured MBAM real-time protection is the cause of this. IIRC this all started after 4.4. I'm running 4.5.8.191 atm. The last old game I had issues with was Galactic Civilisations 3 on Game Pass but it was only until yesterday I managed to make the connection to MBAM as to why it didn't load. Iron Harvest was just released so it should not have loading or compatibility to Win 11 issues.