To extend my limited Macbook Pro storage I keep a 128 GB micro SD always mounted in the SD card reader (thanks to Nifty Minidrive). I use it for static files: music, photo and video files I need to refer to, but that don't change often.

The SD card is formatted in exFAT and from time to time it gets disconnected when I bump my Mac during my commute, and to fix the file system corruption I need to mount it on a Windows PC (since Disk Utility doesn't seem to be able to fix it).

Since I'll use this SD card only on my Mac, should I format it as HFS+ instead?
I've read that a journaled file system can cope better with this kind of problems, and Disk Utility could repair it if needed.

Is there any risk (i.e. excessive wear on the SD card) in formatting my micro SD in HFS+?

Will be HFS+ more reliable than exFAT?

  • No SD card could be called 'reliable'. Don't keep your only copy of anything on one.
    – Tetsujin
    Commented Feb 1, 2017 at 15:16
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    @Tetsujin That's for sure. I still keep a backup of that data on my Time Capsule and on an external USB disk. My question is about which file system is more reliable for this use. You know, it's annoying when you are at work, need to read that file you left on the SD, but the SD isn't mounted because the file system got corrupted, and the other copy you have is at home!
    – gerlos
    Commented Feb 1, 2017 at 15:23
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    I'd take a guess that GUID/HFS+ would be more 'fixable on the fly' but I have no hard evidence, so can't provide an actual answer.
    – Tetsujin
    Commented Feb 1, 2017 at 15:24
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    Since I first wrote my question, I reformatted my SD card in GUID + HFS+, and didn't experience any file system issue even after several "accidents" (mostly card bumped and power loss). I got it disconnected a few times, got warnings that reminded me to clean unmont the card before disconnecting, but didn't experience any real issue. So in for this application, HFS+ seems to be more "robust" than exFAT. Still can't tell if HFS+ can affect SD card life in a different way than exFAT.
    – gerlos
    Commented Feb 23, 2017 at 23:06

1 Answer 1


I tried for myself, formatted the SD card in GUID + HFS+, and after several months it seems more reliable than exFAT for this use case.

When the card is accidentally disconnected the OS shows a notification, but as I unplug and replug the card, the system checks it for defects, and run fsck in the background if needed (it happens rarely, and it takes less than a minute).

So this setup it's a good solution from my point of view.

It's worth remembering that you should use it only for static files, i.e. data that you read often, but write seldom.

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