Hi does anybody know if Malwarebytes have changed their mode of operation? I went to run a scan with the free version at the weekend, was asked to get the most recent updates, a regular happening, and it seems to have installed the Pro version. It's certainly permanently scanning now and slowing the machine down considerably. I uninstalled it and re-installed - same thing. There's been no suggestion that I should be paying anything.
If your computer is running slowly, this would be typical of two (or more) anti-virus programs trying to kill each other off. If you (very slowly) go into control panel, look for uninstall programs, and check how many anti-virus programs you may have. You may need to uninstall Malwarebytes or uninstall the other AV program(s) as two in one computer won't work.
Malwarebytes always has a pre-selected option offering you the 'Premium' (formerly 'Pro') version. So if you fail to remove the tick you'll get a time-limited trial of the paid-for version. Towards the end of the trial period you'll get some prompts asking for payment if you want to keep the 'full' version of the program but you can simply ignore them and Malwarebyes will revert to the free version anyway.