How to fix Microsoft Defender Antivirus from crashing mid scan

Ed 20 Reputation points
2026-08-18T23:32:27.57+00:00

I have been having an issue where when I try to run a quick scan, full scan the scan crashes disabling Microsoft Security features until it restarts the services. I have tried clearing and reloading definition files through Admin command prompt (

MpCmdRun.exe -removedefinitions -all

). I have restarted multiple times including when I performed a reinstall of Windows through System recovery > Fix problems using Windows updates > Reinstall now. Offline scans stall and never complete. Oddly I can run a full scan and select the C drive and it completes.

The errors I see in the4 event viewer are:

In Windows Application logs:

Faulting application name: MsMpEng.exe, version: 4.18.26070.9, time stamp: 0x9a78fc05

Faulting module name: mpengine.dll, version: 1.1.26070.7, time stamp: 0xa09e75a9

Exception code: 0xc0000005

Fault offset: 0x000000000092e48b

Faulting process id: 0x28D4

Faulting application start time: 0x1DD2F635659EBEB

Faulting application path: C:\ProgramData\Microsoft\Windows Defender\Platform\4.18.26070.9-0\MsMpEng.exe

Faulting module path: C:\ProgramData\Microsoft\Windows Defender\Definition Updates{579D2639-ABAF-4D65-BC1A-213EC738E17D}\mpengine.dll

Report Id: 80eecc34-fd5e-4217-a1de-dd7a5309c4da

Faulting package full name:

Faulting package-relative application ID:

In Defender Operations Logs:

Microsoft Defender Antivirus engine has been terminated due to an unexpected error.

Failure Type: Unexpected Crash

Exception code: 0xc0000005

Resource: mpengine.dll

Engine Code: 9626763

Microsoft Defender Antivirus Real-Time Protection feature has encountered an error and failed.

Feature: Network Inspection System

Error Code: 0x80070006

Error description: The handle is invalid. 

Reason: The filter driver was unloaded unexpectedly.

Microsoft Defender Antivirus Real-Time Protection feature has encountered an error and failed.

Feature: Behavior Monitoring

Error Code: 0x80070006

Error description: The handle is invalid. 

Reason: The filter driver was unloaded unexpectedly.

Microsoft Defender Antivirus Real-Time Protection feature has encountered an error and failed.

Feature: On Access

Error Code: 0x80070006

Error description: The handle is invalid. 

Reason: The filter driver was unloaded unexpectedly.

Any suggestions?

Windows for home | Windows 11 | Security and privacy
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Answer accepted by question author
John DeV 169.8K Reputation points Independent Advisor
2026-08-19T00:16:49.5433333+00:00

Hi, good day!

From what I’ve observed here in the forum and across the internet, several users are experiencing the same issue. This could indicate that it may be a bug with Microsoft Defender rather than an isolated problem.

I recommend reporting the issue through the Feedback Hub app so Microsoft is aware of it and can investigate further. Hopefully, with enough reports from affected users, Microsoft can identify the cause and release a fix as soon as possible.

https://support.microsoft.com/en-us/windows/apps/send-feedback-to-microsoft-with-the-feedback-hub-app

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