Synology NAS Volume Read-Only Error: How to Fix It

Q: Why did my Synology NAS volume become read-only?

Synology volumes become read-only when the filesystem detects corruption, bad sectors on hard drives, or critical errors that could lead to data loss. This is a protective measure to prevent further damage while allowing data access.

Q: How long does a Synology filesystem check take?

Filesystem checks can take 1-8 hours depending on volume size and level of corruption. A 4TB volume typically takes 2-4 hours, while larger arrays can take much longer. The process should not be interrupted.

Q: Can I still access my files when volume is read-only?

Yes, you can still read and copy files when a volume is in read-only mode. However, you cannot create, modify, or delete files until the underlying filesystem issue is resolved and write access is restored.

Q: Will I lose data during filesystem repair?

Most filesystem repairs preserve data, but severe corruption can result in some file loss. Always backup critical data before running repairs. The repair process may delete corrupted files that cannot be recovered.

Q: How do I prevent volume read-only errors in the future?

Prevent future read-only errors by using a UPS to avoid power interruptions, replacing drives when S.M.A.R.T. warnings appear, maintaining proper cooling, and running regular filesystem checks during maintenance windows.

Abstract

The Synology NAS volume read-only error occurs when the filesystem becomes corrupted or encounters critical errors, forcing the system to mount drives in read-only mode to prevent data loss. This error means you can access your files but cannot save, modify, or delete them until the underlying filesystem issue is resolved.