What Anti-virus works best with Garry's Mod?

I have just learned that the main reason Gmod won’t work right on my PC, is because of My Anti-Virus program.
I was using Avast! Free Edition and I have uninstalled it, only to see that garry’s mod is running perfectly. It closes properly, and therfe have zero crashes.

The rub is that I need an Avti-Virus program for work, so I need to find a way to install and config Avast! so it will work with Garry’s Mod, or find a A/V that will work with it.

And yes, Disabling the A/V didn’t work at all.
I’m running my PC without an A/V atm.

Suggestions?

Since you’re running 8.1 literally just use the Windows Defender which is built in.

It’s good enough.

[editline]23rd May 2015[/editline]

Why you were having issues with Avast + Gmod is weird. I used to run both before and it was fine.

Avast is known to have false positive detections on some GMod files. So is AVG as far as I know. I am using ESET Smart Security myself.

Then again I did exclude my Steam Library folder.

I know right? It’s just odd as hell. It might be that the A/V is being too anal.
What I have noticed with it, is that Gmod just hangs in memory, and after a few moments after shutting it down, it creates a BSOD.
Forgot to mention I’m using Windows 8.1 Pro x64