Synology NAS Error Code 45: How to Fix It
Medium 30-60 minutes Medium Severity
Verified June 2026
- Error Code
- 45
- Brand
- Synology
- Product Type
- nas
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 30-60 minutes
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Tools You'll Need
- Synology DSM web interface (browser)
- Hyper Backup application (pre-installed on DSM)
- SSH client (optional, for advanced network diagnostics)
- Cloud service admin portal (if using cloud destination)
- Network switch or router admin panel (for network troubleshooting)
How to Fix Error Code 45
-
Check the Hyper Backup Log for Details
-
Verify the Backup Destination is Accessible
Do not remove or reformat the destination drive while a backup may be in progress — this can cause data corruption. -
Confirm There Is Sufficient Storage Space
-
Check and Update Backup Task Credentials
-
Test and Repair Network Connectivity
-
Check DSM and Hyper Backup Package Are Up to Date
Back up your DSM configuration before performing a DSM update. Go to Control Panel > Update & Restore > Configuration Backup. -
Rebuild or Recreate the Backup Task if Corrupted
Deleting a task in Hyper Backup does NOT automatically delete the backup data at the destination. Your existing backup files remain intact unless you manually delete them. -
Verify File System Integrity on the Source Volume
Performing a file system check may temporarily make the volume unavailable. Schedule this during off-hours to minimize disruption.
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When to Call a Professional
Contact Synology support or a qualified IT professional if you suspect physical disk failure (multiple drives showing critical health), if the DSM operating system itself is corrupted and cannot be accessed normally, or if your backup data appears to be lost or inaccessible and you need professional data recovery. If your organization relies on this NAS for critical business data, engaging a managed IT service provider is recommended to ensure backup integrity and compliance.Frequently Asked Questions
What does Synology Hyper Backup Error Code 45 mean?
Error Code 45 in Synology DSM means a Hyper Backup task has failed. This is a general backup failure error that can be caused by an unreachable destination, insufficient storage space, expired credentials, network interruptions, or a corrupted backup task. Checking the Hyper Backup log will reveal the specific sub-error to help you identify the exact cause.
Will I lose my backup data when fixing Error Code 45?
No, simply troubleshooting or editing a Hyper Backup task does not delete your backup data. Your existing backup files remain at the destination unless you explicitly choose to delete them. If you need to recreate the task, Hyper Backup will often offer a 're-link' option to connect to existing backup data without losing backup history.
How do I check why my Hyper Backup task failed in detail?
Open Hyper Backup in DSM and click on the failed task. Then click the log or history icon (it looks like a clock) to open the task log viewer. This will show you timestamped entries for the last backup run with specific error descriptions, such as connection errors, authentication failures, or storage quota issues.
How often should I test my Synology Hyper Backup tasks?
It is best practice to verify your Hyper Backup tasks at least once a month. Check that scheduled backups are completing successfully in the Hyper Backup log, and periodically perform a test restore of a file using Backup Explorer to confirm your backup data is valid and recoverable. Do not assume backups are working just because no alerts appear.
Can a full destination drive cause Synology Hyper Backup Error Code 45?
Yes, a full backup destination is one of the most common causes of Error Code 45. When Hyper Backup cannot write new data to the destination because storage is exhausted, the task will fail. You can resolve this by deleting old backup versions within Hyper Backup's version management settings, expanding the destination storage, or configuring automatic version rotation to prevent the destination from filling up.