Synology NAS Error Code 13: How to Fix It

Q: What does Synology Error Code 13 mean?

Synology Error Code 13 is a disk SMART warning indicating that one or more hard drives in your NAS have detected internal problems that suggest imminent failure. SMART (Self-Monitoring, Analysis, and Reporting Technology) is built into every modern hard drive and monitors key health indicators. When critical thresholds are breached — such as too many reallocated sectors or uncorrectable read errors — DSM raises Error Code 13 to alert you that the drive needs to be replaced as soon as possible.

Q: How urgent is a Synology SMART warning? Can I wait a few days?

A Synology SMART warning is high urgency and you should not wait. While some drives continue functioning for weeks or months after a SMART warning, others fail within hours. There is no reliable way to predict exactly when the drive will stop working. The safest course of action is to back up your data immediately and order a replacement drive right away. Every hour you delay is a risk to your data.

Q: Will I lose my data when I replace the failing drive in my Synology NAS?

If your NAS uses a RAID configuration with redundancy (RAID 1, RAID 5, RAID 6, or SHR with two or more drives), you should not lose data when replacing a single failing drive, as long as the storage pool has not fully crashed. After inserting the new drive, DSM will rebuild the RAID array automatically. However, if you are using RAID 0 or JBOD (no redundancy), replacing the drive will result in data loss on that drive. Always confirm your backup is complete before replacing any drive, regardless of your RAID type.

Q: Which hard drives are compatible with my Synology NAS?

Synology maintains an official compatibility list at synology.com/compatibility. Search for your specific NAS model number (found on a sticker on the unit) and filter by HDD to see all officially tested and approved drives. Synology also sells its own HAT series NAS drives that are certified for use in their systems. Using an unlisted drive may still work but could result in DSM compatibility warnings. Always choose NAS-grade drives rated for 24/7 operation rather than desktop drives for best reliability.

Q: Can I fix a SMART warning without replacing the drive?

No — a SMART warning caused by reallocated sectors, uncorrectable errors, or other critical attributes cannot be repaired through software. These errors indicate physical damage or degradation inside the drive. Some minor SMART issues (like high temperature readings) can be addressed by improving NAS ventilation, but Error Code 13 specifically warns of failure-level problems that require physical drive replacement. Attempting to continue using a drive after a critical SMART warning puts all your data at serious risk.

Abstract

Synology NAS Error Code 13 is a disk SMART (Self-Monitoring, Analysis, and Reporting Technology) warning indicating that one or more of your hard drives are showing signs of imminent failure. This is a high-severity alert that means your drive's internal diagnostics have detected serious problems such as reallocated sectors, uncorrectable errors, or spin-up failures. You should act immediately — back up your data right away and prepare to replace the failing drive before you suffer permanent data loss.