External Hard Drive deny permissions since Sierra Upgrade


macrumors newbie
Original poster
Apr 22, 2016
Hi all

I have an external HD I use to back up my music files and it's worked well but since I upgraded my OS to Sierra recently I can no longer add anymore files - my permissions are 'read only' and cannot be changed. I checked the format of the drive and surprisingly its Windows NFTS!

I guess I'll have to reformat it and load my files on again, but how has this happened? How was I using it before if it wasn't formatted for mac?



macrumors Core
Feb 20, 2009
If you're going to use the drive ONLY on a Mac, you should format it HFS+ with journaling enabled.

Things just work better that way.


macrumors 68040
Feb 17, 2008
Fort Worth, Texas
Most external hard drives sold nowadays are pre-formatted at the factory to NTFS. You do occasionally see drives sold as Mac ready but most are for Windows and formatted for that OS. However, it's easy enough to re-format to HFS+ for use with your Mac.


macrumors regular
Jan 7, 2003
Sydney, Australia
Some drives do come with a special version of the Tuxera NTFS driver which only works with that drive, but you will have to install it first I think. Maybe it came with a handy installer to install an included backup program and the driver at the same time. Being a system-level driver, it would have been disabled in an upgrade, and probably found in the Unsopported folder. And yes, if it truly is NTFS, get a second drive the same size, format as HFS+, use something like Carbon Copy Cloner or SuperDuper to clone it, and reformat the original drive and re-clone (though come to think of it, a true clone might clone the format as well). Now you have a ready-made backup for that drive which you can set up a regular backup regime with using the same clone program using an external case.
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