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 listWindows Security App Not Opening After Update: Fixes
After a Windows update, the Security app may refuse to open—clicking the icon does nothing, or it...
Fix Outlook Calendar Not Syncing with iPhone
You check your iPhone calendar and notice a meeting from yesterday still shows, or a new event yo...
Fix BitLocker Permission Denied When Encrypting External Drive
When you try to encrypt an external USB drive with BitLocker and get a 'permission denied' error,...
Fix Command Prompt Version Mismatch After Windows Update
After a Windows update, you might see errors like "The version of this file is not compatible wit...
How to Fix BitLocker Module Not Found or Permission Denied Errors
When you try to run BitLocker commands in PowerShell or the command prompt and see errors like
Topic paths
Quick titles
High Chrome CPU Usage: Malware Scan StepsFix Get-ChildItem Access Denied Errors in PowerShellWindows Security Service Not Running: TroubleshootTeams Access Denied: IT Admin Troubleshooting ChecklistNet Use Logon Failure TroubleshootingFix Windows Defender 502 Bad Gateway Permission DeniedFix Chrome Backup File Not Found ErrorWindows Security Disappeared Fix