The first thing to do when the application stops working is to restart the computer in order for the modules to restart as well. When Malwarebytes is not working properly, you will be greeted with a message on the interface. Click the buttons indicated to fix the problem and that's it. In case it doesn't work, I recommend that you reinstall the application and all the modules, files, registry items will be restored to the working condition.
Download: https://www.malwarebytes.org/mwb-download/index.html