QNAP NAS Error Code 20: How to Fix It

Medium 1-2 hours depending on volume size Medium Severity Verified June 2026
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Error Code
20
Brand
QNAP
Product Type
nas
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
1-2 hours depending on volume size
Error code 20 on your QNAP NAS indicates that a volume has failed to mount, preventing access to stored data. This usually occurs due to file system corruption, disk connection issues, or a failed disk. Most causes can be resolved without professional help if you follow these steps carefully.
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Tools You'll Need

How to Fix Error Code 20

  1. Check Physical Connections

    Always power off and unplug the NAS before handling internal components to avoid electric shock or data loss.

  2. Access the NAS via SSH

  3. Check Volume Status

  4. Attempt Filesystem Check

    Running fsck on an active volume can cause data loss. Ensure the volume is unmounted first.

  5. Force Remount the Volume

  6. Run QNAP's Volume Repair Tool

    Ensure backups are current before running volume repair.

  7. Replace Failing Drive

    If using RAID, do not remove more drives than the array can tolerate (e.g., RAID 5 can tolerate one failure).

Parts You May Need

Hard drive (if replacement needed)
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Hard drive (if replacement needed)
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Hard drive (if replacement needed)
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Hard drive (if replacement needed)
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When to Call a Professional

If fsck reports severe corruption or the volume still won't mount after repairs, professional data recovery services may be needed. Also call a pro if you are not comfortable using command-line tools or handling hardware.

Frequently Asked Questions

What does error code 20 mean on QNAP NAS?
Error code 20 means a volume is not mounted, so the data is inaccessible. It's often due to filesystem corruption or a disk issue.
Will I lose data if I run fsck?
Running fsck with the -y flag can repair filesystem errors but may also delete corrupted files. Always have a backup before proceeding.
Can I fix error code 20 without command line?
Yes, QNAP's web interface has a 'Repair Volume' option in Storage & Snapshots. Try that first if the volume shows unmounted.
What if the volume is still not mounting after repair?
If the volume fails to mount, it could indicate hardware failure (bad disk or controller). Replace the failing disk or contact QNAP support.
Does error code 20 affect all data on the NAS?
Only the affected volume is inaccessible. Other volumes should work normally unless they share the same physical disks.

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