Fix 'Windows Security Cannot Connect to Microsoft Defender' Error
When you open Windows Security and see the message 'Windows Security cannot connect to Microsoft ...
Checklists for software errors, setup, and tool workflows.
1. Reproduce
2. Isolate
3. Apply
4. Verify
Latest checklists
View listFix Microsoft Store Permission Denied on Mac
If you're seeing a 'permission denied' error when trying to install or update apps from the Micro...
How to Fix Windows Security Login Loop Error
If you're stuck in a login loop where Windows Security keeps prompting for credentials even after...
Fix Windows Defender 404 Error in Command Prompt
When you try to run Windows Defender commands from Command Prompt and get a '404 Not Found' error...
Ubuntu Windows Security Compatibility Troubleshooting Guide
If you run both Ubuntu and Windows on the same machine—either in a dual-boot configuration or thr...
Fix Windows Security High CPU Usage During Malware Scans
You run a malware scan in Windows Security (formerly Windows Defender) and notice your CPU fan ra...
Topic paths
Quick titles
Windows Security Grayed Out: How to FixChecklist for Windows Update Version MismatchWindows Security Full Scan Stuck at 99% – How to FixFix Product Key Doesn't Match Installed EditionWindows Defender and Ubuntu Coexistence GuideFix Windows Update Error 0x80072ee2: Connection TimeoutFix Windows Defender Proxy Error Not WorkingHow to Unpause Windows Search Indexing in Windows 10