Synology NAS Error Code 31: How to Fix It

Medium 30 minutes to 2 hours Medium Severity Verified June 2026
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Error Code
31
Brand
Synology
Product Type
nas
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30 minutes to 2 hours
Synology Error Code 31 indicates a Btrfs scrub has found data inconsistencies on your NAS. This usually means some files are corrupted or hardware issues exist. Follow these steps to diagnose and repair the problem without data loss.
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Tools You'll Need

How to Fix Error Code 31

  1. Identify Affected Volumes

  2. Run a Btrfs Scrub Check

    NAS performance may degrade during scrub; run during low usage.

  3. Check Disk Health

    Back up critical data before replacing any drive.

  4. Review System Logs

  5. Restore from Backup

    Do not overwrite good data; restore only corrupted files.

  6. Replace Faulty Hardware

    Always power down NAS before swapping hardware.

  7. Update DSM

    Back up data and check DSM update release notes for compatibility.

Parts You May Need

Hard drive (compatible with Synology)
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Backup drive
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Hard drive (compatible with Synology)
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Backup drive
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Hard drive (compatible with Synology)
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Backup drive
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Hard drive (compatible with Synology)
Check Price on Amazon
Backup drive
Check Price on Amazon
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When to Call a Professional

If multiple drives fail simultaneously, you cannot restore data from backup, or the error persists after replacing drives, contact a data recovery specialist or Synology support.

Frequently Asked Questions

What causes Synology Error Code 31?
It's caused by Btrfs file system inconsistencies, which can result from disk failures, power outages, or software bugs.
Will Error Code 31 cause data loss?
Not necessarily. The scrub process can often repair minor corruption. However, severe damage may lead to data loss, so backups are crucial.
Can I ignore this error?
No. Ignoring it can lead to more corruption and eventual data loss. It's best to resolve it promptly.
Does this error indicate a failing hard drive?
It can. Check S.M.A.R.T. data to see if any drive is failing. Replace drives with bad sectors or high reallocated counts.
How long does a Btrfs scrub take on Synology?
It depends on volume size and drive speed. For a 4TB volume, it may take 6-12 hours. Scrubs run in the background with minimal impact.

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