SD Cards formatted in FAT32 mount in macOS 15 (Sequoia) as "NO NAME"

Anyone else noticing this since moving to macOS Sequoia?

Recently installed Sequoia 15.6.x from macOS Sonoma.

SD Cards that have a Volume Label under the 8 character limit, formatted in FAT32 always mount as "NO NAME".

However when the same SD Card is formatted as ExFAT - it mounts intact with volume label also correct.

I have tried formatting with official "SD Card Formatter" (both "Quick" and "Overwrite" formatting), formatting in Disk Utility and Terminal. All SD Cards are SanDisk 32GB Extreme Pro (300Mb/s) - but it presents the same issue when formatting a standard USB flash drive, so surely it's a bug with the diskutil backend?

Disk Utility reports no issues with the card, and no directory damage.

Running maOS 15.6.1, iMac 27-inch (intel), 64GB RAM.

Posted on Sep 9, 2025 12:07 AM

24 replies

tbirdvet

Level 6

16,721 points

Sep 9, 2025 06:56 AM in response to oz-macnut

I have seen this but I just right click and rename and it stays.

oz-macnut Author

Level 1

41 points

Sep 9, 2025 03:06 PM in response to tbirdvet

Does it stay when you eject the card and remount it? Do you have the card format as FAT32 or ExFAT?

Sep 10, 2025 10:34 PM in response to oz-macnut

Look in the boot parameter block (BPB):

https://academy.cba.mit.edu/classes/networking_communications/SD/FAT.pdf

See if it’s what you expect.

Appendix 2 is an example.

oz-macnut Author

Level 1

41 points

Sep 11, 2025 01:07 AM in response to MrHoffman

Thanks for that resource MrHoffman. How is it best to check the BPB on the volume with specific tools? Is there a Terminal command that will show that byte blocks?

Can someone reproduce my issue?