New
#1
Cause of corrupt system files?
I've been in the process of removing data from a Win 10 machine for several weeks now, during which time it has not been connected to the internet, and no new programs have been installed on it. However, today, when I was trying to run malware checks on the appdata folder, the anti-malware package that I have installed on the machine began struggling to initiate scans, or completing them instantaneously, or other bugged behaviour. I also have Windows Defender enabled for on-demand scans (and I think occasional background scans), which was also previously working fine, but at the same moment, it began refusing to scan anything at all - e.g. clicking the 'scan now' button gave no response.
To resolve the problem, I initially tried system restore, but that would not complete successfully until I uninstalled the 3rd party anti-malware package from the machine. Even with a successful restore, Windows Defender was still refusing to scan anything, while the restored version of the 3rd party package appeared bugged beyond functionality and had to be removed again.
The problem appears finally to have been resolved by running a scan with the system file checker (sfc /scannow), which reported that it had found corrupt system files and fixed them all. Now Windows Defender is back to working, and the machine *seems* to be functioning normally.
My question is this: on a machine that has not been connected to the internet or had any programs installed on it for weeks, how is it possible for some of the system files suddenly go from uncorrupted to corrupted? Could I have triggered some latent malware on the system by poking around? Could it be the bizarre (and very brief) 'update' that Windows did a couple of days ago even though it can't have had any updates due to not being connected to the internet? Perhaps some conflict between the two anti-viruses? I'm hoping someone can offer an explanation as right now I'm fretting about the malware option.