How might I resolve Windows Defender for Windows 11 stopping during a full scan?

Joshua 41 Reputation points
2026-08-25T22:23:02.3+00:00

Hello, I started a full scan during this morning, and probably around 30 minutes prior to posting this question, I saw that Windows Defender was at 4.5 hours of scanning, and had stated that I can continue to work while it continued scanning. However, after navigating through other applications (such as e-mail), Windows Defender stopped the scan, and did not show that it had been scanning today. It has show that last scanned a quick scan 5 days ago. I would like to ask what might cause this, and how I might resolve this?

Windows for home | Windows 11 | Security and privacy
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  1. Manoel Barros 21,640 Reputation points Independent Advisor
    2026-08-27T01:45:20.9533333+00:00

    Thanks!

    I analyzed the log and saw that the Full Scan was completed. A Full Scan was performed on 08/25/2026 at 9:42 AM and finished at 12:26 PM. You can see this in the Windows Defender log you attached. Click "Filter Current Log" in the right sidebar > Under "Logged," select "Custom" and choose the time range:

    From: Events on 08/25/2026 1:00 AM

    To: Events on 08/25/2026 11:00 PM

    Look for events around the time I mentioned. The "last scan" status likely didn't update due to a bug, or you checked too early. You can check now to see if it has updated, but there is nothing wrong.

    What was the reason for starting a Full Scan? Is it a routine check, or do you suspect something?

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  2. Manoel Barros 21,640 Reputation points Independent Advisor
    2026-08-25T23:29:06.6366667+00:00

    Hi!

    If you are using a laptop, ensure it remains plugged into a power source at all times. If it enters hibernation, sleep, or power-saving mode, the scan could be interrupted.

    For a more detailed analysis, please send me the Windows Defender log: 1. Press Windows + X > Select "Event Viewer" > Double-click "Applications and Services Logs" > Expand Microsoft > Windows > Windows Defender.

    1. Right-click the "Operational" > Save Events As > Put the log name of "System" and save it in an accessible place.

    Now upload this file to a cloud, such as OneDrive, and send me a link. Follow the steps below:

    1. Upload System Log in OneDrive. The link below shows how to do this.

    https://support.microsoft.com/en-us/office/carregar-fotos-e-arquivos-no-onedrive-b00ad3fe-6643-4b16-9212-de00ef02b586#:~:text=No%20site%20OneDrive%2Centre%20com,deseja%20carregar%20e%20escolha%20Abrir.

    1. When uploading, share the files via a link. In the tutorial below you have the steps explained.
    • Release access to "Anyone with link can access".
    • Don’t worry, the logs do not contain personal information from your computer.

    https://support.microsoft.com/en-us/office/compartilhar-pastas-e-arquivos-do-onedrive-9fcc2f7d-de0c-4cec-93b0-a82024800c07

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  3. AI answer

    2026-08-25T22:23:18.9033333+00:00

    Common causes for a Microsoft Defender full scan stopping are:

    1. The scan was stopped before completion. This is recorded as Event ID 1002.
    2. The device restarted during the scan.
    3. The scan timed out. Full scans started by scheduled scan or MpCmdRun have a seven-day limit. Scans started from the Windows Security app do not use that timer.
    4. Power-state changes interrupted the scan, such as sleep, hibernate, or battery-related events.
    5. Resource or file-volume issues can make full scans take a very long time, especially on systems with many files or large archive files such as ZIPs.

    To check what happened on the device:

    1. Open Event Viewer.
    2. Go to Applications and Services Logs > Microsoft > Windows > Windows Defender > Operational.
    3. Look for these scan events:
      • 1000 = scan started
      • 1001 = scan finished
      • 1002 = scan stopped before finishing
    4. Also check restart and power-related events:
      • In the System log, review 6005, 6006, 6007, 6008 for restart activity.
      • Review Kernel-Power events such as 42, 105, 107, 506, 507 for sleep, resume, or power-source changes.

    Ways to reduce the chance of it stopping again:

    1. Run the full scan when the PC can stay awake and plugged in.
    2. Close non-essential apps before starting the scan, since scanning uses processor and memory.
    3. Restart Windows, then run the scan again before opening other apps.
    4. Make sure there is enough free disk space, especially on the system drive, because Defender needs space to remove and quarantine malware.
    5. If the system has many large files or archives, expect the scan to take longer.
    6. Run Windows Update and make sure Defender protection updates are current.
    7. If Defender continually encounters scan errors, submit details through Feedback Hub.

    To review scan results in Windows Security:

    1. Select Start > Settings > Update & Security > Windows Security > Virus & threat protection.
    2. Under Current threats, select Scan options.
    3. Select Protection history.

    If a full scan repeatedly stops, an additional option mentioned in similar cases is to run a scan with Microsoft Safety Scanner to check whether malware is present while the Defender full scan issue is being investigated.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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