Fix Windows Defender Invalid Configuration Error 0x800705b4
When you see error 0x800705b4 in Windows Defender, it usually appears during an update or scan at...
Software comparisons, alternatives, and tool decision notes.
Fit
Decision
Migration
Latest comparisons
Browse labHow to Fix Windows Defender Not Turning On
Windows Defender (now called Microsoft Defender Antivirus) sometimes refuses to turn on or stay o...
Checklist: Troubleshoot Windows Search Permission Denied
When you search for files or settings in Windows and get a 'Permission Denied' or 'Access Denied'...
How to Fix Windows Security Service Unavailable
When Windows Security shows "Service unavailable" or a red banner, your antivirus and firewall pr...
Fixing Outlook Dependency Conflicts That Block Syncing
If Outlook stops syncing email, calendar, or contacts after an update or add-in installation, a d...
How to Enable Windows Defender Service Manually
If Windows Defender won't start or you see warnings that it's turned off, the underlying service ...