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HFS+ External Drive Mounted as Read-only on Mac

When I attached my 2 external USB drives (HFS+) to my MacBook Pro (13-inch 2017), the drives were mounted as 'read-only'. However, when I plug the two drives into 2 different Mac machine: a 2017 15-inch MacBook Pro running High Sierra and an older MacBook Pro running Mountain Lion, they works well. Everything seems fine and no issue reports after checking them for errors. I have formatted them to HFS+ and exFAT, the issue is the same. I can force mount them to be read-write and all works by running sudo mount -u -w -v "/Volumes/HGST Media" in Terminal, but every time I reconnect them, the drives are still mounted as read-only.

Best Answered by

iBoysoft author Connie Yang

Connie Yang

Answered on Monday, April 29, 2024

Since you've checked the disk error, reformatted the two external USB drives, and run the command in Terminal to mount them in read-write mode but still can't get out of this trouble, I suspect that this issue is caused by an OS bug.

You can check if there's any minor update available and update your Mac to try fixing the problem.

  1. Go to the Apple menu > System Preferences > Software Update.
  2. Check if any update is available and start an update.

I also heard from others that the external drive read-only issue may be also caused by the AC-powered USB hub. If you use a USB hub, unplug your USB drives from it and directly connect them to your Mac computer.


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