Unfortunatly many programs have episodes of complete failure causing the user major grief and heartache, Avast, MS, even AVG has done this. Many moons ago I was a happy AVG user, had it setup to only list files it deemed suspicious, leave everything alone, simply present me with a list, this worked great for a long time until that one fateful update. I was complacent, didn't pay attention and failed to notice that the most recent update AVG applied had reset my settings to default which was to simply delete files it deemed were malicious.
I'd spent years creating my own self-extracting exes, archives with all sorts of important data, AVG swept thru my drive deleting every one of them without word one. I didn't even notice for a few days. I have a habit of creating a .sha1 file for each archive, it was a day or 2 later I noticed I had folders with nothing but a .sha1 checksum - where's the associated archive - gone. I really wanted to cry when I opened the AVG log and saw the long list of suspicious files deleted.
I'm the only one to blame I suppose, I guess I could have tried to retrieve the files with software, I didn't. I'm kinda of the opinion I need one computer that has internet access, and one that never leaves the house - no firewall turned on, no Avast, no AVG, no modem, no wireless, only those needed OS updates manually installed, all files installed are fully vetted from the source PC before they're moved. I had a WinXP multimedia workstation I built solely for digital recording, ripping audio/video from CD/DVD, etc. This box lasted about 89000 hours, about 9 1/2 yrs actually - virtually no issues, never a virus, blue screen, mostly at times I pushed it beyond the ability of the very modest AMD processor.
I'm building a modest (for our modern times) mATX box now for a similiar purpose, my new laptop will be the only PC connecting to the outside world. I do realize this isn't ideal for many folks, especially for online gamers and so on, but it can work for some people, it does for me. Oh, I don't share, there is only one(1) PC that everyone in my family can use, and they each have their own, my workstation and my laptop are just that - mine