Windows Defender and Avast

I'm trying to establish what is causing my W7 x64 shutdown to hang at Logging Off, sometimes indefinitely. It's pure hunch but I'm wondering if Avast, which I have fairly recently installed in place of MSE, is conflicting with Windows Defender. I was actually a bit surprised to find that Defender was running, as I'm fairly sure it did not when I had MSE. Maybe I was prompted to activate it - can't remember. Anyway, what do other experienced Avast users do about Defender? Is it required at all when running Avast?

 

Windows Defender is real-time malware protection.

If your Avast has real-time malware protection, then disabling/turning off Windows Defender is a good idea. Either way, you should have real-time malware protection of some sort (separate from real-time AV and firewall).