Hi there, I had this exact same issue yesterday. It popped up saying I needed to update. I did, then it said it needed to restart. I clicked 'No' for the time being as I was doing something. I then noticed it had completely uninstalled. Then restarted my computer, thinking that might continue the process. Nope. Then downloaded https://downloads.malwarebytes.org/file/mb3 from this link which prompted the restart question again. I restarted and still nothing. What is going on? It is clearly affecting numerous people. I'll try downloading the free version and logging into my paid account to see if it works. Fingers crossed.