Synology NAS Error Code 33: How to Fix It
Medium 15-30 minutes Medium Severity
Verified June 2026
- Error Code
- 33
- Brand
- Synology
- Product Type
- nas
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 15-30 minutes
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Tools You'll Need
- Spare SAS cable (optional)
How to Fix Error Code 33
-
Power Down and Inspect Cables
Always power off the device before handling cables to prevent electrical shock or damage. -
Verify Compatibility and Configuration
-
Update DSM and Firmware
Back up your data before performing system updates. -
Perform a Power Cycle
-
Test with Alternative Cables
Use only high-quality SAS cables rated for your NAS model.
Parts You May Need
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When to Call a Professional
If error persists after trying alternative cables and updating firmware, the SAS controller or backplane may be faulty. Contact Synology support or a certified technician for repair.Frequently Asked Questions
What does error code 33 mean on Synology NAS?
It indicates an SAS link error, meaning a communication failure between the SAS controller and an expansion unit or internal backplane.
Can I use any SAS cable for my Synology NAS?
No, you should use a cable that meets Synology's specifications for your model. Using an incompatible cable may cause errors.
Will I lose data if I replace the SAS cable?
If the drives are healthy and the storage pool is intact, replacing the cable should not cause data loss. However, always back up before troubleshooting.
Does error 33 affect all drives?
It typically affects the connection to an expansion unit or specific drives on the backplane. Other drives may remain accessible.
How do I check SAS link status on DSM?
Go to Storage Manager > HDD/SSD. If drives are missing or show errors, check the expansion unit status under Storage Manager > Expansion.