Fix Windows Defender Not Opening Error 404
You try to open Windows Defender and get an error 404 – the page or resource can't be found. This...
Checklists for software errors, setup, and tool workflows.
1. Reproduce
2. Isolate
3. Apply
4. Verify
Latest checklists
View listWindows Activation Access Denied: Step-by-Step Fix Guide
You try to activate Windows, but get an 'access denied' error. This usually means the activation ...
Fix 'Command Not Recognized' Error in Windows Terminal
You type a command in Windows Terminal and get '...' is not recognized as an internal or ex...
How to Fix Microsoft Store Connection Refused Error
If you see a 'connection refused' error when opening Microsoft Store, it usually means the app ca...
Fix Windows Security Not Starting After Update
After a Windows update, you might find that Windows Security won't open, or it shows a blank wind...
How to Fix Windows Update Certificate Trust Error
You see a message like "Windows could not search for new updates" or "An error occurred while che...
Topic paths
Quick titles
Open Command Prompt as Admin in Windows 11Windows Terminal Service Unavailable ChecklistCommand Prompt Fix for DNS Probe Finished No InternetmacOS Cron launchd Permission Denied Error GuideHow to Resolve BitLocker 0x8031004b After ResetVS Code Remote SSH Timeout: Quick FixesHow to Fix PowerShell WinRM Connection RefusedFix Windows Defender Service Not Starting