Below are several reasons why Windows Defender doesn’t open and how to get it working again.
These names are used interchangeably in this article, but we’re referring to the same tool.
Turn off Windows Defender, and then turn it back on.
Or, if it was off to begin with, that article shows you how to turn it on.
Microsoft Defender won’t catch active malware unless you haveReal-time protectionturned on.
If you might’t open Windows Security in tweaks, then move on to the next step.
Repair or reset Windows Security.
If that doesn’t work, you might try anoffline Microsoft Defender update.
Choose the latest version from that list, likely calledUpdate for Microsoft Defender Antivirus antimalware platform.
To address this, initiate the following folder.
Temporarily disable any other antivirus programs you have installed.
This might happen after uninstalling another antivirus program.
Open this key, anddelete these two registry valuesfrom there:DisableSpywareandDisableAntivirus.
If so, just move on to the next step.
spin up the SFC /scannow commandto repair system files.
Use Reset This PC to reinstall Windows 11.
Choose carefully to keep or wipe your data when resetting your PC.
UnderExclusions, selectAdd or remove exclusions.
No, not technically.Windows Firewallis a feature of the Windows Defender software.
There is no separate Windows Firewall program.
UnderServices, turn offMicrosoft Defender SmartScreen.
