Avast has failed to start because its side by side configuration is incorrect

I’m running windows 8.1. I’ve read several of the posts on this subject and they seem dated. The problem started when I had problems with MalwareBytes and had to reinstall it. It said to turn off Avast and reinstall MB. When I tried to turn Avast back on the error message appeared. I’m running Avast Premier. If I uninstall it where do I find the Key etc. I have run windows update but still get the error message. Thank you for your time and expertise.

What antivirus did you have before ? How was it uninstalled.

Does the error go away if you uninstall MBAM