Fix Windows Defender 404 Not Found Error on Windows 10
You click to open Windows Defender Security Center and see a 404 page, or the Settings app shows ...
Checklists for software errors, setup, and tool workflows.
1. Reproduce
2. Isolate
3. Apply
4. Verify
Latest checklists
View listHow to Fix Windows Defender Stuck on Loading Screen
If Windows Defender (Microsoft Defender Antivirus) gets stuck on a loading screen or shows a blan...
Reset Windows Search Settings to Fix Connection Error
When Windows Search stops returning results or shows a connection error, it's often due to corrup...
Fix Microsoft Store Error 0x80070424 on Windows 11
When you try to open or download an app from the Microsoft Store on Windows 11, you might see err...
Fix Windows Search Indexer Dependency Conflicts
When Windows Search stops returning results or the indexer crashes repeatedly, a dependency confl...
Fix OneDrive Sync Error 0x8004de40: Reset Settings
If you see error code 0x8004de40 when trying to sync files in OneDrive, it usually means the sync...
Topic paths
Quick titles
How to Flush Chrome DNS CacheWindows Search 404 Error TroubleshootingFix Windows Update Module Not Found After Clean InstallChrome Token Expired Error 400 FixFix Windows Search Not RespondingWindows 10 Command Prompt Network Error TroubleshootingTroubleshoot Command Prompt Module Error Post-UpdateHow to Resolve Untrusted Certificate in Windows