What is WINDOWS-DEFENDER-STUCK?
WINDOWS-DEFENDER-STUCK shows up as a low-severity Windows operating system fault. Windows Defender Antivirus is causing 100% CPU or disk usage and is not responding. Typical causes include security definitions not updated and exception for system folders is not set. The steps below are ordered to resolve this efficiently.
Common Causes
- Security definitions not updated
- Exception for system folders is not set
- Conflict with other antivirus software
Step-by-Step Fix Guide
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1
Update virus definitions manually
Update virus definitions manually tends to be the quickest win here, addressing the most typical cause of WINDOWS-DEFENDER-STUCK.
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2
Add exceptions for game folders and developer tools
A recurrence usually points to a rarer windows instability cause, which is what the following steps are meant to catch.
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3
Go to Settings → Windows Security → Virus & threat protection → Manage settings
"Go to Settings → Windows Security → Virus & threat protection → Manage settings" targets security definitions not updated, one of the documented causes of WINDOWS-DEFENDER-STUCK.
Commands & Diagnostics
Update-MpSignature
Start-MpScan -ScanType QuickScan
Frequently Asked Questions
The leading cause of WINDOWS-DEFENDER-STUCK is security definitions not updated, though exception for system folders is not set and conflict with other antivirus software also show up in our reports.
Most WINDOWS-DEFENDER-STUCK reports resolve after "Update virus definitions manually". The rest of the guide above is there for the cases that don't.
As a low-severity issue, WINDOWS-DEFENDER-STUCK is more of a stability annoyance than a hardware risk — the steps above should clear it up.
You shouldn't need to. Work through the guide above first — a reinstall is only worth considering if none of those steps help.
Sometimes. Microsoft regularly releases patches that fix known BSOD triggers including WINDOWS-DEFENDER-STUCK. Make sure Windows is fully up to date via Settings → Windows Update before attempting more advanced fixes.
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