Windows Defender Compatibility

Can I run Avast alongside Windows Defender in a Windows 8.1 computer?

No. Disable Windows Defender then install avast. It’s a very bad idea to
have two resident anti-viruses at the same time.

Read this for more information.

Thanks for your reply. I am aware of the problems caused by running two AV’s but they describe Defender more like anti spyware software then AV and I was not sure if it could be kept active to be run as a stand alone.

WD on W8 and above is a full AV…!!

On a Win8 system, Windows Defender should automatically disable itself when you install avast [or any other recognized anti-virus program].