Mac OS Sequoia not recognizing USB Flash Drives

my external drives exhibits the same problem, but it's okay if i use a USB-C adaptor OR I reboot with it attached - and it mounts. By the way this only happens with my M1 Macbook Pro, does not happen with my M4 Pro Mini

Still the same problem.

It's not only a flash drive detection problem, but a huge USB bug.

No USB device are working anymore since sequoia, where everything was working like a charm juste before.

It seems to be relative to the way they manage usb communication.

It's a shame for the price of the device that I can't work anymore with it.

I will ask a refund, it's absolutely not acceptable.

Can you try shutting down the computer (not just sleeping it) connecting the drive to the usb port, making sure the drive is powered on if it has separate power, and then turn the computer on with it connected?

I’ve been able to kick this problem by doing this and then just have all the usb drives that were giving me trouble mount reliably afterwards.

I saw upthread someone had gotten their device to work after leaving it connected for a long time, so I left my Garmin plugged into my Mac overnight. The next morning it was still not connected but after unplugging it & plugging it in again it connected & Garmin Express was able to see it. It's continued to work through several disconnections & reconnections - it's slow to mount (takes 20-30 seconds) but so far it's working.

This is a well knowed issue. Apple will not fix ever.

Fat32 or exfat Drive is not recognized except for low energy device like USB dongles.

you will notice diskutil is bricked.

you can try 2 solution

1 - Use a power supply if you use an HUB

2 -use a Windows PC and Repair disk. the tool repair not will do nothing, but once finished, put the drive on mac and will work

Sequoia 15.2

Someone has already reported it works only once. I have the same situation – mounting remote controller FrSky Teandem X18S works seamlessly only the first time I plug it into the Macbook. All attempts after that fail.

me too. I took a bunch of data off an old macbook pro with a busted screen, and now I can't even get the usb drive to connect to my new macbook pro using the same dongle. Pretty pathetic, and frustrating.

Had a similar problem on Sequoia (15.3 I think?) on M1 Macbook: USB flash drive did not show up in Finder or in Disk Utility but DID show in system diagnostics. Here was the fix: when I connected the USB flash drive, for a fraction of a second there was a pop-up asking if I wanted to allow the device to connect. I had to make a slo-motion movie with my iPhone to read it. To resolve that, I had to go into settings and switch from asking me to allowing USB - I set it to Automatically when Unlocked. Worse for security, but after that the drive showed up immediately in Finder.

I just purchased a new MacBook Pro with M4Pro and it has Sequoia 15.3.2 and my USB flash drive will mount fine.

I just upgraded my MAc Studio with M1 Max to Sequoia running 15.3.2 and that same USB drive won't mount. I am using USB-C.

Luckily the Mac Studio doesn't have any problems with my ProGrade Digital CF Express readers and my 2 External G drives. They all are using USB-C.

Attempting to connect my My Book external hardware. it shows on the system, however unable to access.

Any help is appreciated!

In my case, no the drives really aren't mounted.

I CAN manually mount them using Disk Utility, but that is a pain.

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

Found one. It was ExFAT and mounted just fine.

The only way it works with this SSD is with the option I mention. If I change to anything else, it doesn't mount.

i had to buy a usb c adapter and plugged my thumb drive into it and thumb drive worked with this metheod

Exactly, and it’s not my External Hardrive alone, it doesn’t even recognize my IPhone 15 any more, all it does is charge my phone . And it started as soon as I updated.