I am having a problem with an external HFS+ USB drive on a MacBook Pro running High Sierra:
When I plug the drive into the computer, it gets automatically mounted as
read-only. I have to manually remount it to make it
sudo mount -u -w -v /Volumes/hdd
However, if I plug the same drive into my older MacBook Pro running Mountain Lion, the drive is mounted
read-write as expected.
I have erased (formatted) the disk many times over, and also tried
diskutil verifyDisk and
diskutil verifyVolume, everything seems clean.
Any ideas on how to troubleshoot / fix this problem?