QNAP NAS Error Code 16 (Disk Write Failure): How to Fix It

Medium 30 minutes to 2 hours (depending on test durations and RAID rebuild) High Severity Verified June 2026
Summarize with ChatGPTSummarize with ClaudeSummarize with Perplexity Add as Preferred Source on Google
Error Code
16
Brand
QNAP
Product Type
nas
Severity
High
DIY Difficulty
Medium
Estimated Fix Time
30 minutes to 2 hours (depending on test durations and RAID rebuild)
Error code 16 on your QNAP NAS indicates a disk write failure, meaning the system cannot write data to one or more hard drives. This high-severity error can lead to data loss if not addressed promptly. Below are steps to diagnose and resolve the issue.
Ad

Tools You'll Need

How to Fix Error Code 16

  1. Back Up Your Data Immediately

    Data loss risk: Do not continue until you have a backup if possible.

  2. Check Disk Health via QTS

  3. Run a SMART Test

    SMART tests can take hours; plan accordingly.

  4. Check File System Integrity

    Running a file system check on a large volume may be time-consuming and should be done during maintenance windows.

  5. Inspect Physical Connections

    Unplug the power cord before opening the NAS to avoid electric shock.

  6. Test Drives in Another System

    Handle drives carefully to avoid static damage.

  7. Replace Failing Drive

    If using RAID, ensure the array is in a degraded but operational state before swapping.

  8. Rebuild RAID Array (if applicable)

    RAID rebuild can take hours or days depending on array size; avoid heavy I/O during rebuild.

Parts You May Need

NAS-grade hard drive (e.g., WD Red, Seagate IronWolf)
Check Price on Amazon
SATA data cable
Check Price on Amazon
NAS-grade hard drive (e.g., WD Red, Seagate IronWolf)
Check Price on Amazon
SATA data cable
Check Price on Amazon
NAS-grade hard drive (e.g., WD Red, Seagate IronWolf)
Check Price on Amazon
SATA data cable
Check Price on Amazon
NAS-grade hard drive (e.g., WD Red, Seagate IronWolf)
Check Price on Amazon
SATA data cable
Check Price on Amazon
Ad

When to Call a Professional

If you are not comfortable opening hardware, if multiple drives are failing simultaneously, or if data recovery is needed after a failed drive, consult a professional data recovery service or QNAP support.

Frequently Asked Questions

What causes QNAP error code 16?
Error code 16 indicates a disk write failure, usually caused by a failing hard drive, loose cables, file system corruption, or a faulty NAS controller.
Can I ignore QNAP error code 16?
No, ignoring it can lead to data loss. The error signifies that the NAS cannot write data, which may cause crashes or corruption. Address it immediately.
Will replacing the drive fix the error?
If the error is due to a failing drive, replacing it and rebuilding the RAID array should resolve the issue. However, if the problem is with the NAS enclosure or controller, further troubleshooting is needed.
How do I know which drive is causing the error?
In QTS, go to 'Storage & Snapshots' > 'Disks/VJBOD' and look for disks with 'Warning' or 'Bad' status. You can also check system logs under 'System Logs' for disk-related errors.
What type of hard drive should I use as a replacement?
Use a NAS-rated hard drive such as WD Red, Seagate IronWolf, or similar. Ensure it matches the capacity and interface (SATA or SAS) of your existing drives.

Related Error Codes