“windows defender advanced threat protection is blocking installation of avast broswer” among other things. I watched in task manager as I hit install and MsSense.exe just started draining Ram and CPU and instalation failed. It tried to reinstall it, same result. Security update happened hours before this
Running default Microsoft Windows Defender?
No other antivirus installed?
Operating system?
Did you get the Avast Browser file from here?: https://www.avast.com/secure-browser#pc
https://support.avast.com/en-ww/article/secure-browser-faq/#pc