Windows Defender for Windows 10 and other Editions
Microsoft introduced Windows Defender Advanced Threat Protection to enable customers to detect, investigate and respond to Advanced Attacks on their Networks.
Windows Defender is built into Windows 10 and you do not need to download it.
Windows defender for Windows 8, 8.1 and Windows RT does not require you to download or install Windows Defender. Windows Defender is already built-in and provides protection against malware.
Windows 8 onwards, Microsoft have replaced Microsoft Security Essentials, you don’t need to download it separately—Windows Defender is already included and ready to go.
But if you’re looking to protect a PC with an older version of Windows like Windows 7 or Windows Vista, you can use Microsoft Security Essentials to help guard against viruses, spyware, and other malicious software.
Troubleshooting Windows Defender is turned off or not working
- Check if you have any 3rd Party Antivirus program which might be causing issues with Windows Defender.
- Open Action Center and see if you are able to enable Windows Defender.
- Run services.msc to open Services Manager. Ensure that the Windows Defender service is started and set to Automatic.
- You can try to re-register the following dll files and see if this helps you. Run each command at the command prompt one by one and hit Enter:
- Try enabling Windows Defender from the Registry.
(delete) = On
1 = Off
If still it does not work, then please contact Microsoft Support.