Unable to access External Drives and Disk Utility after updating to macOS Sonoma.

This solution worked for me.

Firstly, I have a Sandisk SSD USB-C (formatted in NTFS). It was working fine in Sonoma until today where it wouldn't mount at all, and Disk Utility wouldn't even load any of my Disks/Volumes while the drive was plugged in. I'm not sure what's causing the problem but Apple support wasn't much help.

While attempting to access the drive in Recovery Mode on my M1 MacBook Air I was unable to even load it via Disk Utility. Disk Utility just gave me a loading curser animation.

So... I had to connect the drive via a USB-C to USB-A dongle to my older Intel MacBook Pro (which only has USB-A), run disk repair via Terminal, and UNMOUNT, and EJECT, the drive safely via terminal. Then it mounted just fine back on my M1 MacBook Air in Sonoma 14.2.1. (The repair told me that my disk was fine, btw.)

You can find instructions on how to run a repair on a volume via Terminal online. Here's an example:

https://gist.github.com/bzerangue/dca8fc2d63309ba2bd9f

You then have to unmount the drive using "diskutil unmountDisk /nameofdisk"

Then, also eject the disk using "diskutil eject" command. (Again, instructions for this are easy to find online.)

I think the problem is that the ExFat and NTFS disks/volumes aren't ejecting properly in Sonoma. So, a good solution would be to actually use the terminal to unmount and eject the volumes/disks manually to be safe.

I agree with you 100%. This is BS worthy of Windows 8. I pay premium dollars for Apple hardware "That just works." And I end up spending days trying to get an external SSD drive working again that was working perfectly fine on Ventura 13.6. I'm lucky it was relatively easy to restore to Ventura. Sonoma is dead to me!

My 2TB IMAC is a year old, everything worked fine until the upgrade to Sonoma, I can't see any of my saved files to my WD external hard drive, have they been wiped out? I'm in need of a solution to save my files and clear up some space on my HD again, so will Apple resolve this, or will all my saved files be lost forever?

I paint and do photography work on my computer and need to know what the best solution for saving and not losing my work.

I'm not as tech Savy as some, but I can muttle my way around. Thanks!

2 Tips that I have found that have helped me.

Having upgraded my Mac from a 2019 Intel iMac with a 2tb Fusion Drive to a Mac mini pro with 500gb storage I needed an external SSD for my files .The spontaneous ejection when the Mac went to sleep is an issue that Apple has not solved . Perhaps they prefer you to buy large amounts of iCloud storage instead or maybe the Sonoma is, in reality, still in Beta form.

Also I had an old 3Tb WD Red mechanical drive which I had put in a Ugreen caddy for a mirror storage where speed was not an issue .

I purchased a crucial x9 external ssd and attached to the Mac mini with its usb c connector. To stop it spontaneously ejecting when the Mac went to sleep I tried disabling sleep mode in system settings. This did not always work so I installed a free program from the App Store which has solved the problem. Why Apple could not incorporate such functionality I fail to understand. Maybe it will appear secretly in a future update!

The WD red was another issue which was not solved . This would eject and then fail to mount through Disk Utility. First aid showed no issues with the disk and certainly swapping out the USB cable had no effect. However I tried various formatting protocols - APFS, Mac journalised and finally ExFAT. The ExFAT seems to be the only stable one for this particular drive which now seems rock solid once more.

My external HDs drop off after about a minute or two. It says Disk not ejected properly. Currently running a Black Magic 4 external drive unit with 3 drives. They drop off on by one. They also stopped working with Time Machine back up. The data is still on the removable drives. Sonoma just forgets the drives are there and chucks them off. Also, disk utility doesn't recognize these Samsung SSDs either. I thought that it may be the hardware, but on further inspection it seems that this is happening on a regular basis. I don't want to spend the countless hours going back to Ventura and reconfiguring. Please send help!

Although i 'seem' to now have a stable external drive tree....i did connect my Media Player today and watched it get kicked out over and over again...

Will Apple Ever Release a Bug Free OS?

Will consumers ever be free from doing the troubleshooting Apple should have done BEFORE releasing an OS?

I find it disrespectful to those of us who have spent buckets of dough on a product that is Supposed to be awesome...yet it annoys us due to it NOT being ready to truly release

I have a similar issue that's driving me nuts! Two external disks, both in exfat format that often just freeze when trying to eject them! I just cannot get them unmounted even using diskutil force unmount command. They just get stuck ejecting or sometimes even hang the whole machine! Only thing that works is restarting the machine but then it keeps happening again! Never had this issue before Sonoma.

Macbook pro M3 Max, Sonoma 14.3

i really have to say im extremely disappointed in apple as of late... you spend over 3k on a laptop which only has thunderbolt ports and you have to buy an adapter or usb c hub for everything, additionally they release a new os (mac os sonoma) which makes exfat drives stop working. I find it incredible that Apple software engineers make over 200k and come out with non-working products and no patches in sight at least for right now smh... guess ill be forced to downgrade back to mac os ventura and hopefully i can use my external drives again

I run a couple of Apricorn 2TB secure HD's. They have to be formatted with exFAT as I use them at home (MAC) and work (Windows). I have the same issues as described in this forum and it is about time Apple rectified it. My alternative is just to scrap MAC completely.

I have noticed that small thumb drives have no issue switching between platforms. To get the Apricorns to work I have to do a disc repair in Windows (nothing is 'repaired'). Then it will open on my MacBook. If I then shut it down, even correctly, it won't re-open and Disc Utility won't open with it plugged in and doesn't see it if I open D/U and then plug in the Apricorn. I need to take it back to the Windows computer at work.........so I need to make sure I don't need to access the drive twice while at home.

Come on Apple, you should be better then this.....

**** right they caused this with the update I can not get my data off my external either and it’s your whole life well not no more after this the Mac will have limited use and I will go back to writing and mailing to have record of what I do in the future if it has to be done by these machines that now have control of our lives how long are we going to put up with this conditioning I for one am going to stop doing what they tell me and I will be telling them we don’t need you

I did include the name of the app that stopped the ejection of drives as the computer sleeps which corrupts them and makes them unmountable subsequently. This app, available on the App Store, seemed to solve this problem for me but Apple deleted the post giving the name as it is their policy to disallow the naming and recommending 3rd party programs. It seems to me that they need to aknowledge and fix the problem with Sonoma to put an end to this thread of dissatisfaction and frustration. Having to downgrade to Ventura is a lengthy procedure and ultimately we want the upgrades to maintain security on our systems.

With the amount of unhappy folks out here that have been battling Sonoma i am surprised Apple hasnt done ANYTHING.

I have gotten to a point where my Mini is not crashing daily and my drives are ok...

BUT,

i cannot mount my Surfans media player, computer cant find it at all..

I will chime in and say i am thoroughly disgusted with Apple and their inability to get this fixed.

one can only imagine the amount of complaints they see about Sonome, just wish they would get off their arses and correct the issues..

One would think a new release would Solve things...not with Apple...

Reformatted older Samsung 860 and 870 drives using disk utility. I haven't loaded those drives yet with data, and they are stable. On my brand new WD_BLACK SN770 2TB Media I noticed that it will drop out sporadically, especially if I load the drive up with data. Maybe Sonoma has a hard time reading the control chip when the drive is populated with data.

I thinks Apple has made restriction in using over 1TB external drive in macOS Sonoma, because same enclosure supports 500GB and 1TB MVME SSD but for 2TB doesn't detect the drive after 1st recognise, but the drive works well in Ventura in same machine and other OS.

Please anyone need to find patch or apple will do it future updates

srajiv wrote:

I thinks Apple has made restriction in using over 1TB external drive in macOS Sonoma, because same enclosure supports 500GB and 1TB MVME SSD but for 2TB doesn't detect the drive after 1st recognise, but the drive works well in Ventura in same machine and other OS.

Please anyone need to find patch or apple will do it future updates

I’ve got a 5TB, three 2TB, and a 1TB drive all running without issue on my Sonoma M1 Mini.