I just updated my iMac M1 to run Sequoia and now my USB flash drives are not recognized. My external hard drives are recognized as are my external SSD's. I have seen online that I am not the only one with this issue, but nowhere have I found a fix. Is this something that can be fixed or do I have to wait for a update?
iMac 24″, macOS 15.0
Solved:
I (unfortunately) updated 2 Airs and a Pro to Sequoia and had trouble with them recognizing all external hard drives and flash drives after the update. Luckily I saw a security (hand icon) window flash quickly on one of them as I was plugging a drive in. So I thought it might be a security issue, scrolled down in Settings->Privacy and Security -> Accessories. Setting the option to "Always Allow" makes it work. Setting it to Always Ask does not seem to work since the window just quickly flashes by, not allowing you to confirm access. Enjoy!
WillemfromZwolle, an Apple Support told me to attach the unit to my Studio M1, and just wait wait, maybe 8 hours - that might be needed for the attaching protocol to work it out once there is a fault.
they don't but oddly my external hard drives and iPad show up with no problem, so that's why I checked my devices on other computers to make sure it wasn't the usb drives or midi devices that had an issue, and they work perfectly fine on other computers that don't have the sequoia 15.2 update
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
In my case, no the drives really aren't mounted.
I CAN manually mount them using Disk Utility, but that is a pain.
So you have other USB-A things that work in that port or different USB-A port to try?
Do they show up in Disk Utility?
Does anything work in the USB ports?
Try connecting the external drive in windows, and "fix the errors" when it says in Windows, and after the Fix then try plugin to Mac and it should show up.
Do they appear in System Information? Do they appear in Didk Utility?
@cat-girl: This thread has grown beyond a manageable size, so I urge you to start a new thread, and add an Etrecheck report to your post to save time.
Same issue Late 2023 Macbook Pro 16 M3 Pro 18GB
15.0 (24A335)
Just called Apple about it, and they want to take it in for service
Weird behavior from any type of mass storage.
Initially I tried moving some files from my NAS to a known working SD Card formatted w/FAT32.
It hung, so I had to cancel it. Then I noticed I couldn't format it, stuck "Creating partition map", it wouldn't auto mount
So I tried various flash drives, some worked okay, then broke just a few minutes later.
Some USB drives wouldn't show up at all in Disk Utility, even when booting directly into recovery mode.
On the support call we ruled out faulty flash drives, and USB C adapters.
I am also having the same issue. I am using a Cruzer Fit drive, plugged into a USB-C adapter formatted to MS-DOS FAT32. Prior to this upgrade it worked fine, I have many files on this drive and could access, update and save with no issues. After the upgrade the drive does not show under locations in Finder; however, when I go to system information -> hardware -> USB it shows there under USB 3.1 Bus. Also, when I select a recent word document saved on this drive it gives an error that the file can't be opened. Frustrating as I plug the drive into another MAC and the drive shows in Finder and I sent some of the files through email. tried many reboots but the issue still remains, hopefully fixed soon.
One more for the pile:
My mother bought a new Embroidery Sewing machine and it takes USB thumb-drives but only in FAT16 or FAT32 format.
So Now I've discovered that for whatever reason, I cannot get her 2019 5K iMac which is running macOS Sequoia 15.1.1 to mount any FAT16 or FAT32 USB drives. It can even format usb drives with these formats in Disk Utility and then Disk Utility will give an error that it couldn't mount the disk afterwards.
I can mount ExFAT or macOS formated USB drives on her iMac just fine... but of course those aren't supported by the sewing machine.
To top this off, my Aunt is visiting and had her M1 MacBookAir running macOS Sequoia 15.1 and it *can* mount any and all FAT16 or FAT32 USB drives I throw at it. Also, my 2022 M1 Max Mac Studio running macOS Sequoia 15.1.1 can mount any and all of these FAT16 and FAT32 formatted USB drives too.
My mother's 2019 5K iMac is the odd duck out that just won't do it. You can see the disks grayed out in Disk Utility but they will not mount.
I feel like every new major release of macOS just comes with more awful bugs that never seem to get fixed with later releases.
I solved the issue of SSD discs disconnecting/not mounting:
1) I discarded my cheap or old (say 2010-2018) drives bought for example from Aliexpress. These probably contain old software and hardware interfaces; maybe even these are incorrectly labelled USB-C for instance. Which version???
2) I bought an OWC 4TB USB with Thunderbolt 5 interface (even though my Studio is Thunderbolt 4)
3) I have a modern (2024 design) Hagibis Thunderbolt 4 where I put an existing NVME into.
Since then I have had no problems.
The take-away: you really have to upgrade your storage hardware too once in a while, as protocols change.
You want the speed too, don't you? And enhanced security.
15.1 update seems to have fixed the problem.
Try looking in ‘about this Mac’ > ‘USB’. That’s where I found it…
Mac OS Sequoia not recognizing USB Flash Drives
