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 listHow to Fix Microsoft Store Download Pending Error
You tap Install in Microsoft Store, but the download stays stuck on "Pending" and never starts. T...
Fix Windows Defender Missing After Update
After a Windows update, some users find that Windows Defender is missing from the system tray, Se...
Fix Windows Update Error 504 Gateway Timeout
You're trying to run Windows Update and get a '504 Gateway Timeout' error. This typically means t...
Fix Windows Activation High Memory Usage After Update
After a recent Windows update, you might notice your PC running slowly and Task Manager showing t...
Fix Windows Update Assistant Not Working on Mac
If you're running Windows on a Mac via Boot Camp, Parallels, or another virtual machine, the Wind...
Topic paths
Quick titles
Windows Search Indexing Rate Limit Stuck – Practical FixesWindows Update Cannot Connect: Step-by-Step ChecklistTroubleshoot Black Screen After Windows UpdateTroubleshoot VMware Virtual Network Adapter Not InstalledHow to Reduce Windows Defender CPU Usage in Windows 10How to Resolve Windows Activation Failed to Start SetupHow to Resolve Task Scheduler Version MismatchFix 'Windows Update Auto Start Service Not Found' Error