Windows 10: 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.

:)

 

Corrupted file RAR

If the archive has been created using WinRAR, why don't you try WinRAR itself? It has a built-in repair feature for repairing corrupted archive (ZIP as well as RAR). Follow the steps given below:

• Open WinRAR application in your system.
• Now click on File tab > Open or simply press Ctrl+O.
• A small window "Find Archive" will pop up. Locate the corrupt RAR archive from your system directory and select it.
• Now click Open button.
• Click Tools tab > Repair archive or simply press Alt+R.
• Again a small window "Repairing File name.rar" will pop up.
• Now click Browse to select a location to save the repaired archive.
• Check the box "Treat the corrupt archive as RAR" and click OK.
• WinRAR will start repairing of corrupt RAR archive. Once it gets completed click Close.

I hope the above steps will help you repair the corrupted RAR archive.

Thanks.

 

corrupt Folder in File Explorer

Hi,

this might be caused by a virus or a corrupted files. To assist you in resolving the issue, we suggest running the System File Checker. It helps scan and restore corrupted files. Check this link on how to know the step-by-step procedure in performing
System File Checker.

Let us know if you need further help.

 

Corrupt file - Can't fix. [Fixed]

Hi Vincent,

Thank you for posting your concern here in Microsoft Community.



Before proceeding, please check if the same issue occur when logged in through a different user account.

Ref: http://windows.microsoft.com/en-us/windows-10/getstarted-set-up-accounts

Please perform the below steps and see if it helps to resolve the issue.

This issue may happen due to system file corruption. I suggest you to run System file checker. System File checker (SFC) scan is done to check if there are any corrupted system files that could be causing this issue. Kindly follow
the below given steps:

• Press Windows key + X, select
  Command prompt (Admin) to bring up elevated Command prompt.
• In Command prompt type sfc/scannow and press enter.
• Restart the computer.

If no corrupted system files were found in the previous state, then I suggest you to try the following steps:

• Open command prompt by pressing Windows key + X and selecting “Command prompt admin”.
• In command prompt, type the following commands and press Enter after each command:

DISM.exe /Online /Cleanup-image /Scanhealth

DISM.exe /Online /Cleanup-image /Restorehealth

• Close the command prompt and restart the PC and check if it works.

Hope this information helps. Please post us if you need any further assistance with Windows.

Thank you.