I dont keep malwarebytes installed on my computer, instead I have the .exe file stored in my documents. I do have PCTools antivirus that runs all the time, if on the rare occasion I do end up with a virus, I turn off the PCTools one and then install and run the Malwarebytes, not having it actually installed seems to keep the virus from preventing it running, learned that a few years ago trying to get rid of a particularly stubborn one. I've gotten a few in the last year or so that were amateur viruses it seemed as all I had to do to get rid of them was run a system restore to a previous date, all the "professional" viruses disable that ability it seems.