Caution: macOS Sonoma May Not Support ExFAT

UPDATE Jan. 4, 2024. On macOS Sonoma 14.2.1, I can format and access ExFAT-formatted SSDs and thumb drives. Hopefully, this means Apple has fixed this problem.

Mary Peterson sent me the following caution:

“Had a couple exFAT formatted drives (in case I had to share with PC client). But Sonoma is unable to mount those drives. Lots of discussion in Apple Community forums on the issue. Ended up using EaseUS software which could see into the drives and let me copy them. Some files were corrupted but was able to copy all my video clips and more. Am now making sure drives are formatted APFS. And I bought lots of cheapish external drives so I can keep 3 copies of critical files! I should have known better…”


In researching this, it appears that there are issues with ExFAT in Sonoma. Here’s a link to Apple Discussions on this topic.

Apple’s Sonoma Release Notes state:

“The implementations of the exfat and msdos file systems on macOS have changed; these file systems are now provided by services running in user-space instead of by kernel extensions. If the application has explicit checks or support for either the ExFAT or MS-DOS file systems, validate the applications with those file systems and report any issues.”

In other words, there were issues, but these may now be fixed. Maybe.

If you have critical data stored on ExFAT drives, BE SURE to copy it to a non-ExFAT volume before upgrading. It is better to be safe than sorry.


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23 Responses to Caution: macOS Sonoma May Not Support ExFAT

  1. Simon Morice says:

    Hi Larry,

    Thanks for the post, it confirmed my experience. I had exactly the same problem with a brand-new Crucial X10 Pro SSD. I spent an hour or so with Apple Support, my new M2 and a late 2103 Macbook. We got a handle on the problem and found a workaround.

    The issue prevented Resolve and Premiere from saving. Before the .1 upgrade, Sonoma could read and write to the ExFAT SSD but not very reliably. Sonoma 14.1 hates ExFAT and kills it.

    It does seem you have to reformat to APFS and then the sun comes out. All seems to be working just fine now.

    The support agent has informed the developers, so I guess there’ll be a less psychopathic 14.2 out in due course.

    Regards

    Simon

    • Larry says:

      Simon:

      Thanks for letting us know.

      APFS is fine if we are exclusively Mac. But if we need to move files between Mac and windows, ExFAT is essential.

      I hope Apple fixes this.

      Larry

    • Noel Cosgrave says:

      Sonoma 14.4.1 just borked my exFAT-formatted SDXC card, so the problem has not gone away, and it doesn’t only impact on transfers between Windows and MacOS, but also loading images and video from digital cameras, where the exFAT format is the de-facto standard.

      • Larry Jordan says:

        Noel:

        Sigh… I’m very sorry to read this. It is incredibly frustrating. macOS Sonoma 14.4.1 has lots of problems. However, I regularly use Sonoma 14.3.1 and 14.5 to work with EXFAT cards from DSLR cameras and have not had problems.

        I’m hoping that your problem can be remedied by upgrading to version 14.5, which was released last week.

        Larry

  2. Tod Hopkins says:

    I highly recommend getting an ntfs for Mac driver rather than messing with exfat which has always been problematic. Paragon, Tuxera, iBoysoft, and others have commercial versions, not terribly expensive and often discounted. There is a free open source driver, NTFS-3G, which is not yet install compatible with Sonoma but you can find instructions for a hack install.

    • Larry says:

      Tod:

      Good to know. I’ve always been leery of NTFS.

      larry

    • Patrick M Blackard says:

      I’ve been using MacDrive on Windows machines for 15 years. I can keep my files in Mac formats (including APFS) and use them on either machine. In that time editing has been on Windows Avid, Mac Final Cut, Mac Premiere, and now Windows Premiere. Field transfer is on an M1 MacBook Pro. When I send camera footage to clients, they mostly want Mac formatted files.

  3. Also latest FCP and Sonoma do not transmit signal to external monitor through Blackmagic 3-G mini-monitor.

  4. Al B. says:

    Been using Paragon for years. Works great

  5. Andrew Findlay (Bristol UK) says:

    I have to say I formatted a Crucial X10 Pro 2TB SSD to ExFat in Sonoma on an M2 MBP running Sonoma 14.1 that I have used for shuttling between myself and the post house… and it’s been working fine. It mounts, reads and writes.

    Guess I’m lucky then?

    However, since reading this article, I have backed it up to an APFS SSD drive!

  6. Mark Roseman says:

    On Sonoma rsync and cp are both not working properly with ex-fat. Rsync gives all copied files today’s date and does not retain the original file date. This has affected the wonderful copy app dropsync. At the moment, it can be used only with external drives in apple native formats.

  7. Rick Lee says:

    ExFAT drives seem to work fine in Sonoma (I’m using 14.1) if you format it with Allocation Unit Size to 128K. To do that in Windows, use Disk Manager, Format, and set the Allocation Unit Size to 128K (don’t use Default, it’s 1024K in Windows).

    Cheers.

    • chris says:

      Thanks buddy. That has solved the problem for me. I’m not sure what Allocation Unit Size defaulted to when I formatted it originally in Monterey, but doing it in Windows, with 128K, has worked. Thank you for posting.

    • Ed says:

      So in summary if I partition an external drive to exFat for the Windows files i should be able to read and write to the exFat files from a MacBookPro [2021 M1].

      • Larry says:

        Ed:

        Interesting. I haven’t tried this, but partitioning a drive with one side HFS+ (or APFS if it is an SSD) and the other ExFAT should enable the ExFAT version to be read on Windows.

        Try it and let me know what happens.

        Larry

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