Windows Defender Service Troubleshooting Checklist
If Windows Defender won't start, won't update, or shows error messages like "Service stopped" or ...
Checklists for software errors, setup, and tool workflows.
1. Reproduce
2. Isolate
3. Apply
4. Verify
Latest checklists
View listHow to Fix Command Prompt Hanging When Running as Administrator
You right-click Command Prompt and select “Run as administrator,” but the window either doesn’t a...
Chrome Permission Denied Error: Causes and Fixes
You try to upload a file, access a camera, or visit a site in Chrome and see a “permission denied...
Fix Windows Defender Threat Service Stopped Startup Type Error
If you open Windows Security and see a message that the threat service has stopped and the startu...
Fix PowerShell 'Could not load file or assembly' Error
When you run a PowerShell script or cmdlet and see an error like Could not load file or ass...
Fix Missing Windows Security After Update
After a Windows update, you might find that Windows Security (formerly Windows Defender) is missi...
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Quick titles
Resolve Teams 404 Page Not FoundFix Windows Update Error 0x80070005 by Resetting ComponentsHow to Fix Chrome Permission Denied IssuesHow to Resolve Chrome 502 Error Post-UpdateFix Windows Terminal SSH Connection Refused ErrorHow to Resolve Windows Defender Real-Time Protection Error 0x80070422Fix Maven Dependency Issues in Continuous IntegrationHow to Restart Windows Defender After Update