how to stop MRT

Since this morning my macbook (15" mid 2012, 2.6ghz I7 18gb ram. OS Sierra 10.12.6) started raging. Memory started clogging, my CPU was constantly running. My macbook heated up and the fan started blazing. After taking a look at the activity monitor I found a mysterious process called 'MRT'. It was consuming al my computing power.

After some searching on the web I found that this is a programme made by Apple which searches for malware after installing a new security update. It should also terminate itself after running it's check (which should only last for a few minutes). I took a look a the file (system>library>coreservice>mrt) and saw it was created at the 23th of August 2017. Meanwhile I had restarted my computer a few times without any result. I reset all my permissions, I reset SIP (System Integrity Protection), and all without any result. I also tried to disable the process in the terminal, again without any result. I tried to remove the files which are linked to MRT, but that was impossible - even in recovery.

I am quite desperate now, because my computer is becoming quite unusable due to this problem. I've read everything on the internet about this problem, but no solution was able to solve the problem.

Is there anyone who had the same problem? Is there anyone who can help me?

Everardus