If one external USB drive appears read-only in ZimaOS while other drives can be written normally, do not assume NTFS is the reason. Current ZimaOS documentation lists NTFS, exFAT, FAT, EXT and Btrfs as read/write-capable formats for USB storage.
The original ZimaOS 1.4.3 thread did not reach a verified root cause. IceWhale support asked the user to preserve the environment and provide a reproducible case, so the safest conclusion is that this was a device-specific mount or filesystem-state problem, not a documented NTFS limitation.
Check the Current Filesystem Support First
The current ZimaOS disk format table lists NTFS as read/write for USB disks. It also lists exFAT, FAT16/32, EXT2/3/4 and Btrfs as read/write-capable, while APFS and XFS are not supported in that table.
This matters because the forum post started from the assumption that an NTFS disk would be read-only. On current ZimaOS, that assumption is no longer a useful diagnostic shortcut.
Compare a Working Drive With the Read-Only Drive
Because several USB HDDs worked on the same system, compare one working disk and one failing disk before changing anything. Check the filesystem type, mount path, connection through the USB hub, and whether the failing drive was previously removed without a clean unmount.
If the issue appears only through a hub, connect the drive directly to the server for one test. This separates a filesystem problem from power, bridge-chip, cable, or USB-enclosure behavior.
Do Not Reformat Terabytes of Data as the First Step
A read-only mount can be a protective response to a filesystem problem. Reformatting may hide the original cause and creates unnecessary migration work. First make sure the data is backed up, then inspect the disk health and mount state before deciding to recreate the filesystem.
If you are moving application libraries between disks, the ZimaOS data migration guide is useful for avoiding broken application paths during a storage change.
When the Drive Still Mounts Read-Only
Record the ZimaOS version, disk filesystem, enclosure model, whether the disk works directly without the hub, and any storage or kernel messages around the time the drive is attached. That gives support a reproducible difference between the working and failing disks.
The original thread is best treated as an unresolved 1.4.3 case. Current documentation confirms that NTFS itself is not supposed to force USB storage into read-only mode.
