Fix Windows Defender error code 0x80073afc

If you see Windows Defender throw up an error code 0x80073afc when you boot your Windows computer or when you try to run Windows Defender manually, then the cause for this could be corrupted Windows Defender files. This error could also occur if third-party security software is interfering with the smooth functioning of this Microsoft Security Client. If you face this problem, here’s what you can do to resolve the issue.

Windows Defender error code 0x80073afc

Windows Defender error code 0x80073afc

If you create a System Restore point, you can try to undo any modifications on your computer, by performing System Restore. In case, you do not have a habit of creating a System Restore point; I suggest you start doing so because it is a very strong feature that will let you fix your computer in a number of scenarios.

We will be undertaking the following fixes for error 0x80073afc for Windows Defender-

  1. Check the status of all Windows Defender related Services.
  2. Re-register concerned DLL files.
  3. Using the Registry Editor.
  4. By checking the Environmental Values.
  5. Using System File Checker.

1] Check the status of all Windows Defender related Services

Open the Windows Services Manager.

Windows Defender error code 0x80073afc

Right-click on the following service, one after the other and open Properties. From the drop-down of Startup Type, select Manual – and make sure that they is Running by manually pressing the Start button.

  • Windows Defender Advanced Threat Protection.
  • Windows Defender Advanced Network Infrastructure.
  • Windows Defender Antivirus Service.

Right-click on the following service, and open Properties. From the drop-down of Startup Type, select Automatic – and make sure that it is Running.

  • Windows Defender Firewall.

2] Re-register concerned DLL files

You might have to re-register some DLL or Dynamic Link Library files on your computer. So launch CMD (Admin) and re-register the following DLL files by executing these commands one after the other:

regsvr32  atl.dll
regsvr32  wuapi.dll
regsvr32  softpub.dll
regsvr32  mssip32.dll

Reboot your computer for the changes to take effect.

3] Using the Registry Editor

Hit the WINKEY + R button combination to launch the Run utility, type in regedit and hit Enter. Once Registry Editor opens, navigate to the following key-

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options

Now, check if you find some DWORDs named as MSASCui.exe, MpCmdRun.exe, MpUXSrv.exe, or msconfig.exeIf you don’t, just move to the next fix. But if you do see them, delete all these keys or folders.

Reboot your computer for the changes to take effect.

4] By checking the Environmental Values

Start by typing View advanced system settings in the Windows Search Box. Select the appropriate result.

A new mini window will pop up. Navigate to a tab called Advanced. On the bottom part of the mini window, click on the button named Environment Variables…

For the variable name of %ProgramData% make sure that the value for it is set to C:\ProgramData.

Select OK to save the settings.

5] Using System File Checker

Right-click on the Start button and click on Command Prompt (Admin), type in the following command to run System File Checker and then hit Enter.


sfc /scannow

Restart your system after the scan is completed.

Hope something here helps you!

Posted by on , in Category Windows with Tags
Anand Khanse is the Admin of, a 10-year Microsoft MVP Awardee in Windows (2006-16) & a Windows Insider MVP. Please read the entire post & the comments first, create a System Restore Point before making any changes to your system & be careful about any 3rd-party offers while installing freeware.

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