Frequently Asked Question
Why can my Mac read my WD drive but not save new files to it?
ACE SUPPORT · WD
First check the drive format. macOS normally reads an NTFS volume without native write access. A format mismatch is different from a permission error or a failing disk. Preserve existing files before choosing a supported way to write to the drive.
Applies to
WD My Passport, My Passport Ultra, My Book and other direct-attached storage on macOS. A drive already formatted as APFS, Mac OS Extended or exFAT needs a different diagnosis if it becomes read-only.
Before you begin
Reformatting erases existing contents. Do not erase or run repair operations on an unbacked-up drive containing important data. Ownership changes do not add native NTFS write support to macOS.
Work through these checks
- Select the drive in Finder and inspect its information, then check the volume format in Disk Utility. Note the exact error, macOS version and whether the drive previously relied on an NTFS driver. Do not select Erase.
- If it is NTFS, use a Windows computer to read and write the volume where available. For a Mac that previously used an authorised third-party NTFS driver, check that driver's current macOS compatibility through its publisher. Do not download an unknown driver or weaken system security to force an old one to load.
- If files are readable, copy the important data to separate healthy storage and open representative copies. Confirm the backup is complete before planning any change to the original volume.
- For a drive intended only for current Macs, consider a supported Mac format. For a drive shared between supported Windows and macOS computers, exFAT may fit the requirement. Check other intended devices and backup-software requirements before choosing.
- If the volume is already a natively writable format, check available capacity and the affected user's access. A sudden read-only state after errors or disconnects needs a file-system or hardware assessment, not an automatic permission reset.
Confirm the result
After the appropriate supported change, create a harmless file, reopen it and safely eject the drive. Reconnect it to every intended platform and confirm the test file remains readable.
When to contact us
Contact our Support Specialist if the format is unclear, the disk disconnects, files cannot be read, or a previously working NTFS driver stopped after an update. Provide the format and software versions privately.
Updated 260530