Windows 8 and 8.1 – Cannot start Windows Defender - Error 577 Windows cannot verify the digital signature for this file while starting the service – Turn ON windows defender opens system32 folder

Error 577: Windows cannot verify the digital signature for this file. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that might be malicious software from an unknown source.

Method 1: Windows Defender Not Working After Upgrading To Windows 8.1

Press  Windows + R and type wscui.cpl in the Run dialog box and Click OK

  

Click Turn on now or if you see there the Launch button, click it.

Check If it launches Windows Defender

  

Method 2: App remover

If there is no antivirus or security tool installed in the computer Download and run

APPremover to confirm

http://www.appremover.com/download

Run the application

Wait for the scan to detect the security Software

Select the Antivirus application

Click on Remove

Reboot may be required.

Method 3: Tweaking tool

Note: Ensure to Turn off security application installed in the computer before running

Tweaking tool

Download and install tweaking tool from below Link http://www.tweaking.com/content/page/windows_repair_all_in_one.html

Click Start repairs 

Click Start

Click Yes 

Click Select All

Uncheck non essential repairs listed below:

•    Repair CD/DVD Missing/Not Working,

•    Repair Windows Sidebar/Gadgets,

•    Repair Windows Snipping Tool

Click Start

Reboot the computer if prompted 

Method 4: DISM tool

Open Command prompt as administrator

Execute each of the below commands

Sfc /scannow

DISM.exe /Online /Cleanup-image /Scanhealth

DISM.exe /Online /Cleanup-image /Restorehealth