Windows Defender Antivirus Error 577

How to Fix Windows Defender Antivirus Error 577?

To resolve the Windows Defender Antivirus Error 577 problem, carry out the troubleshooting steps mentioned below.

  • Try to download the PC Repair tool from the manufacturer website.
  • Install and launch the PC Repair tool on your computer.
  • Click the Start Scan button to start the scanning process.
  • Once the problem is detected, click the Repair All button.
  • This will resolve the Windows Defender Antivirus Error 577 problem. If the issue remains unresolved, follow the instructions given here.
  • You can switch to a third-party antivirus software instead of using the built-in antivirus program, i.e., Windows Defender on the Windows computer.
  • The Windows Defender antivirus program offers only basic protection and it lacks some advanced features to protect the computer.
Windows Defender Antivirus Error 577


  • Hold the Win and R keys together on the computer’s keyboard.
  • The Run dialog box will appear on the screen.
  • Once you type ‘regedit’ in the Open field, select the OK option.
  • As soon as the Registry Editor window appears, go to the ‘HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender’ key on the left panel.
  • On the main panel, find the DisableAntiSpyware option and select it.
  • Change the value from o to 1 in the Value Data field and click the OK button.
  • Likewise, change the value for DisableAntivirus.
  • Exit the Registry Editor window and navigate to the C:\Program Files\Windows Defender location.
  • Run the MSASCui.exe file.

Removing the Third-party Antivirus Program

  • The built-in Windows Defender antivirus program will not work properly if you have installed any third-party antivirus on the Windows computer.
  • Because, the third-party antivirus will interfere with the Windows Defender program.
  • Try to remove or uninstall the installed third-party antivirus software from the Windows computer.

Notification Center:

  • Enable the Windows Defender antivirus from the notification center.
  • Navigate to the notification center at the lower-right corner of the screen.
  • If you see the alert message, click it. Now, the Windows Defender Antivirus Error 577 will be turned on.

Security Permissions:

  • Before you proceed with the following instructions, create a registry backup.
  • Launch the Registry Editor dialog window and search for the ‘HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender’ key on the right panel.
  • Right-click this key and select the Permissions option.
  • Click the Advanced button followed by the Add button.
  • After you click the Select a principal option, fill both the Object Name and Username fields and click the Check Names button.
  • Confirm that the entered username is correct, click the OK button.
  • Once you check the Full Control field, click OK -> Enable Inheritance -> Apply -> OK.

Restarting the Windows Defender Service:

  • Enter ‘services.msc’ in the Run dialog box.
  • Note: The Run dialog box can be launched by holding the Win and R keys at the same time.
  • Search for the Security Center service, right-click it, and select the Restart option.
  • Go to the Services window, find the Windows Defender service, and select the Start option.
  • Now, both the Security Center and Windows Defender service will start.
  • If the Windows Defender 577 problem persists, create a user account.
  • If required, contact our technical support members by clicking the Call button mentioned below to get remote assistance in resolving the Windows Defender Antivirus Error 577 problem.