Windows Defender Scan Stuck in Loop Windows 11 Fix [2026]

Quick Answer: Defender scan stuck due to corrupted scan cache. Restart Windows Security service and run MpCmdRun to reset scan engine.

Fix

Restart-Service windefend

"C:\Program Files\Windows Defender\MpCmdRun.exe" -RemoveDefinitions -All
"C:\Program Files\Windows Defender\MpCmdRun.exe" -SignatureUpdateCheck

Settings → Privacy & security → Windows Security → Virus protection → Scan options → Microsoft Defender Offline scan

Againly runs check_security_baseline to detect Defender issues.

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Instant Resolution

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Works on Windows 10 & 11 • No credit card required