Synology NAS Error Code 55: How to Fix It

Medium 30-60 minutes Medium Severity Verified June 2026
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Error Code
55
Brand
Synology
Product Type
nas
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-60 minutes
Synology DSM Error Code 55 indicates a failure with NFS (Network File System) exports on your NAS device. This typically means the NAS cannot properly share folders over NFS to connected clients, which can prevent Linux, Unix, or other NFS-compatible systems from accessing shared data. The error is usually caused by misconfigured NFS rules, service conflicts, corrupted export settings, or DSM software issues that can be resolved without professional help.
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How to Fix Error Code 55

  1. Verify the NFS Service is Enabled

    Do not make changes to NFS settings while active client machines are reading or writing data, as this can cause data corruption on connected clients.

  2. Review and Correct NFS Export Rules

  3. Restart the NFS Service

    If you use SSH, only run commands you fully understand. Incorrect commands can affect system stability. Ensure SSH access is secured with a strong password or key-based authentication.

  4. Check DSM Firewall Rules

  5. Update DSM to the Latest Version

    Always back up your critical data before performing a DSM update. Go to Control Panel > Update & Restore and create a configuration backup before proceeding.

  6. Reset NFS Configuration via SSH

    Editing system files via SSH carries risk. Incorrect edits to /etc/exports can make shared folders inaccessible. Make a copy of the file before editing: 'sudo cp /etc/exports /etc/exports.bak'

  7. Run a DSM Repair or Reinstall

    A DSM repair should not delete user data, but as a precaution, back up all important data to an external drive or cloud before proceeding.
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When to Call a Professional

Contact Synology Support (support.synology.com) if Error Code 55 persists after completing all steps, including a DSM repair. You should also seek professional help if you are uncomfortable using SSH to edit system files, if the NAS has experienced a hardware failure (such as a failed drive affecting system volumes), or if NFS was working correctly and stopped without any configuration changes — this may indicate a deeper firmware or hardware issue. Business-critical environments with SLA requirements should engage Synology's enterprise support team directly.

Frequently Asked Questions

What does Synology Error Code 55 mean?
Synology Error Code 55 is a DSM NFS export error. It means the NAS has encountered a problem exporting one or more shared folders over the NFS protocol, preventing NFS clients such as Linux or Unix systems from mounting those shares.
Can Error Code 55 cause data loss on my Synology NAS?
Error Code 55 itself does not cause data loss — it is a configuration or service error related to NFS sharing. Your data remains on the drives. However, if NFS clients lose their connection mid-transfer, files being written at that moment may be incomplete. Always verify file integrity after resolving the error.
Why does Synology Error Code 55 keep coming back after I fix it?
If the error returns repeatedly, the most likely causes are a corrupted DSM NFS configuration that regenerates incorrectly after reboots, a network issue causing the NFS service to fail on startup, or a DSM bug in your current firmware version. Updating DSM to the latest release and performing a DSM repair are the best long-term solutions.
Do I need to reboot my Synology NAS to fix Error Code 55?
A full reboot is not always required. Restarting just the NFS service (via DSM or SSH command 'sudo synoservice --restart nfsd') is usually sufficient. However, if you perform a DSM update or repair, a reboot will be required as part of that process.
Which Synology NAS models are affected by Error Code 55?
Error Code 55 is a DSM software-level error and can affect any Synology NAS model running DSM, including the DS, RS, and SA series devices. The fix steps are the same regardless of model, as they all involve DSM settings and the NFS service configuration.

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