Mac OS Sequoia not recognizing USB Flash Drives

Same here. I have a 4TB M2 drive mounted in an Acasis enclosure and then through a Kensington SD5700T Hub.

This worked perfectly fine without fail until update to Sequoia.

All hub ports and other connected hardware show in USB hardware report. The 4TB drive does not mount.

If I unplug the drive to hub or even the hub to Mac connection it appears as soon as they are connected.

Has anyone rolled back to Sonoma and its fixed the issue?

[Edited by Moderator]

Similar issue. Mac Studio M1 will not mount an XQD card (Formatted in Nikon Camera) and USB flash drives. SD cards in the Mac Studio slot work just fine. All worked smoothly before updating to Sequoia.

All cards and USB's show in Apple System Report with all details. Tried all the reboot etc tricks.

I have been in touch with Apple. Escalated case to OS engineers. Hopefully there will be a solution shortly. Very inconvenient.

Correct! I'd probably burn down the house trying to use Terminal.

Confirmed: 15.01 still not connecting external drives/SD cards.

Same for me - none of the settings mentioned in the above posts results in FAT32 USB flash drives appearing on the desktop or finder.

This is more than an inconvenience for me - I have a 3D printer farm that only works with FAT32 USB Flash Drives.

In many cases this is a USB C accessory issue.

Solution:

Use a basic USB 2 to USB C adapter

**NOTE: I was experiencing this issue. I was connecting my drives via an Apple USB-C Digital AV Multiport Adapter. This adapter was 100% the issue. Not the software. Not drivers. The adapter. Switching to a basic dongle/adapter resolved the issue.

DavidWMB wrote: "...What's up with Apple? Do they even know and care what's going on?"

Make sure they know:

Feedback - macOS - Apple

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I have found that USB sticks formatted for FAT mount reliably but ones formatted for exFAT don't.

Biggest mistake I made was updating to Sequoia. None of my USB drives are recognized. I've tried everything to fix this, but to no avail.

On MackbbokPro M1, on Sequoia, One Drive on my Sat Nav (SD64), comes up unreadable, but shows in diskutility and can be mounted. However the main sat nav drive is greyed out and says uninitialised...however both work normally on an intel based 2019 27" iMac ... obviously I cannot reformat a Sat Nav drive, so no cannot update routes when travelling.

What a mess they made of it... any suggestions?

Sequoia 15.1 update does not fix the USB Flash Drive problem on my site (Mac Studio M1), but network and bluetooth problems.

Sequoia 15.1 update does not fix the problem, I still can't use my external storage. I feel very sad. (MacBook Air M2)

In my case the flash drive shows up in disk utility as Disk4.

In the Disk Utility you can mount it with the typed mount command, dismount or unmount is using the command and eject it using a typed command. It has a FDisk_partition_scheme of Windows_FAT_32

In Finder - Settings - General I have attempted the "Show these items on Desktop" and "Show these items on Sidebar" and the drive does not show.

I had to go dig into the sofa cushions to find a USB stick to try.

When I plugged it in, Finder gave me the this disk not recognized dialog. Figured it was just bad.

Tried formatting and then it worked fine. I don't know how it was formatted before.

If you can actually mount the drive using Disk Utility or Terminal, copy the data off and reformat. If it is a camera card, use the camera to format it.

I'll dig through some other furniture to see if I can find another to test.

I have been using SD cards on my M2 MacBook Pro without issue. The USB Stick I tested was on an M1 Mini.

I have updated to 15.01. Still no joy. So frustrating! Hasn't made any difference, except for making my MacBook more unstable and slow, with that dreaded spinning wheel when opening applications. What's up with Apple? Do they even know and care what's going on? Again, I have to reiterate that my biggest mistake was "updating" to Sequoia!!