QNAP NAS Error Code 15: How to Fix It

Medium 2-4 hours (including RAID rebuild) High Severity Verified June 2026
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Error Code
15
Brand
QNAP
Product Type
nas
Severity
High
DIY Difficulty
Medium
Estimated Fix Time
2-4 hours (including RAID rebuild)
QNAP Error Code 15 indicates a disk read failure, meaning your NAS is unable to read data from one or more hard drives. This can lead to data loss or system instability. Follow this guide to diagnose and resolve the issue.
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Tools You'll Need

How to Fix Error Code 15

  1. Backup Critical Data Immediately

    Do not remove or replace drives before backing up if possible, as this may worsen data loss.

  2. Check Drive Health Using QNAP Dashboard

  3. Perform a Quick S.M.A.R.T. Test

  4. Replace the Failing Drive

    Unplug the NAS from power before handling drives to avoid electric shock or data corruption.

  5. Rebuild the RAID Array

    Do not power off the NAS during RAID rebuild as it can cause data loss.

  6. Run a Full S.M.A.R.T. Test on All Drives

Parts You May Need

Replacement hard drive
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Replacement hard drive
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Replacement hard drive
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Replacement hard drive
Check Price on Amazon
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When to Call a Professional

If you are not comfortable opening the NAS, or if the RAID rebuild fails, contact a data recovery specialist or QNAP support. Also seek professional help if multiple drives fail simultaneously or if you need data recovery from a failed drive.

Frequently Asked Questions

Can I ignore Error Code 15?
No, ignoring this error can lead to complete data loss. Replace the failing drive as soon as possible.
Will I lose data if I replace the drive?
If your NAS is configured with RAID 1, 5, 6, or 10, you can replace the drive without data loss. With RAID 0 or JBOD, data loss is likely. Always back up first.
How do I know which drive is failing?
Log into QTS and check Storage Manager for disks with warning icons or S.M.A.R.T. errors. The error log might also indicate the drive number.
Can I use a different brand or size of hard drive as a replacement?
Yes, as long as it meets the minimum capacity requirements of your RAID array and is compatible with your QNAP model. Check the QNAP compatibility list.
What if the RAID rebuild fails?
Try rebooting the NAS and rerunning the rebuild. If it fails again, contact QNAP support or a data recovery service.

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