Synology NAS Error Code 22: How to Fix It

Medium 30-90 minutes depending on approach (longer if physically expanding storage) Medium Severity Verified June 2026
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Error Code
22
Brand
Synology
Product Type
nas
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-90 minutes depending on approach (longer if physically expanding storage)
Synology NAS Error Code 22 indicates that a DSM volume on your Synology NAS has run out of available storage space. When this happens, the system cannot write new data, which can interrupt backups, file syncing, surveillance recordings, and other critical services. Resolving this error requires freeing up space on the affected volume, expanding storage capacity, or reorganizing how data is distributed across your drives.
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Tools You'll Need

How to Fix Error Code 22

  1. Identify the Full Volume in DSM

    Do not delete any files or folders without first confirming what they contain. Accidental deletion of system or application data can cause service failures.

  2. Check Storage Consumption by Shared Folder

  3. Delete or Move Unnecessary Files

    Back up any important data before deleting files. Once the Recycle Bin is emptied, files cannot be recovered without a separate backup.

  4. Clear Surveillance Station Recordings

  5. Remove Old Hyperbackup or Backup Archives

    Only delete backup versions after confirming you have a more recent valid backup. Deleting all backup versions removes your ability to restore historical data.

  6. Check and Clear System Logs and Temporary Files

  7. Expand the Volume with an Additional Drive

    Always power down the NAS before physically installing drives unless your Synology model supports hot-swapping. Refer to your NAS model's hardware installation guide. Back up all data before modifying storage pool configuration.

  8. Rebalance Data Across Multiple Volumes

  9. Set Up Storage Threshold Notifications

Parts You May Need

3.5-inch internal hard drive (NAS-rated)
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2.5-inch SSD or hard drive (NAS-compatible)
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Drive tray or caddy (model-specific)
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3.5-inch internal hard drive (NAS-rated)
Check Price on Amazon
2.5-inch SSD or hard drive (NAS-compatible)
Check Price on Amazon
Drive tray or caddy (model-specific)
Check Price on Amazon
3.5-inch internal hard drive (NAS-rated)
Check Price on Amazon
2.5-inch SSD or hard drive (NAS-compatible)
Check Price on Amazon
Drive tray or caddy (model-specific)
Check Price on Amazon
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When to Call a Professional

Contact Synology support or a qualified data storage technician if: you are unable to log into DSM due to the error, the volume shows degraded or crashed status in addition to being full, you need to expand storage but are unfamiliar with RAID or storage pool operations and risk losing data, or if a drive in your NAS has failed and needs professional data recovery. Synology offers paid support contracts and their community forum (community.synology.com) provides expert guidance for complex storage scenarios.

Frequently Asked Questions

What does Synology Error Code 22 mean?
Error Code 22 on a Synology NAS means the DSM volume has run out of available disk space. The system cannot write new data to that volume until space is freed up or the volume is expanded. Services that write to the full volume — such as backups, file sync, and surveillance recordings — will stop working until the issue is resolved.
Will Error Code 22 cause me to lose data?
Error Code 22 itself does not cause data loss — it simply prevents new data from being written. However, if you delete files to resolve it, those files are permanently lost once the Recycle Bin is emptied. Always back up important data to a secondary location before making storage changes.
How do I quickly free up space on my Synology NAS?
The fastest ways to free space are: empty the Recycle Bin in File Station, delete old Surveillance Station recordings, remove outdated Hyper Backup versions, and delete unused Docker images and containers. These four areas commonly account for the majority of unexpected storage consumption on a Synology NAS.
Can I add more storage to my Synology NAS to fix Error Code 22?
Yes. If your NAS has an empty drive bay, you can install a new compatible hard drive and use Storage Manager to expand the storage pool and volume. If all bays are occupied, you can replace existing drives one at a time with higher-capacity drives. Always check Synology's hardware compatibility list at synology.com before purchasing drives.
How do I stop Synology Error Code 22 from happening again?
Set up storage threshold notifications in Control Panel > Notification so DSM alerts you when a volume reaches 80–85% capacity. Also configure automatic cleanup rules in Surveillance Station and Hyper Backup so old recordings and backup versions are purged regularly. Planning for at least 20% free space at all times is a good practice for NAS storage health.

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