Caution: macOS Sonoma May Not Support ExFAT

Posted on November 4, 2023 by Larry Jordan

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

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Simon Morice says:

November 6, 2023 at 5:00 am

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:

November 6, 2023 at 5:07 am

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
Tod Hopkins says:

November 6, 2023 at 5:32 am

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:

November 6, 2023 at 5:49 am

Tod:

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

larry
Howard Silver says:

November 6, 2023 at 6:43 am

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

November 6, 2023 at 6:57 am

Been using Paragon for years. Works great
Larry says:

November 6, 2023 at 7:18 am

Howard:

Good to know. Thanks!

Larry
Larry says:

November 6, 2023 at 7:21 am

Al:

Good to know.

Thanks!

Larry
Andrew Findlay (Bristol UK) says:

November 6, 2023 at 11:56 am

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!
Larry says:

November 6, 2023 at 12:25 pm

Andrew:

It is always good to know when something works. Thanks for writing.

Larry