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

I lost an 8TB hard drive just after the upgrade to Sonoma. It was formatted for Time Machine in APFS - you don't get an option to change format style on a new drive for Time Machine and also a 4TB Mac extended journaled disk, and a 2TB WD exFAT.

One after another they started to drop off and for no reason. Apple support - what support? - you may as well p@ss into the wind! No one wants to acknowledge this or do they? You get a case number and that's it. I tried recovery with various software programs.

You fork out thousands of €uro for the computer which they say will do everything you need, you find out then they no longer come with large amounts of memory. You buy ext. hdd's or ssd's more hundreds if not another thousand €uro for storage, not to mention extra cloud storage for emergency contingency.

My computer is less than 4 months and I wonder what next.... maybe the internal ssd or the M1 or M2 chip just as the computer passes the final days of its warranty cover.

A clear statement is needed from this company what is causing the problem and when it will be fixed, people do not have endless amounts of money to throw after bad.

In my opinion, formatting external hard drives is not a solution. It was working before for the EXFAT drives. Apple should release an update to fix this issue.

For me on M1 PRO MBP the issue looks like Sonoma is somehow reliably corrupting external exFat SSDs on every shutdown. If I unmount my SSDs before shutting down, they mount and work flawlessly on next start. But when I shutt down with the external SSD mounted, then it becomes unusable. To solve this state I... connect the drive to a Windows PC. It works but offers to scan and repair the drive as it detected errors. After the short repair procedure under Windows magic happens! It works again under Sonoma again! Until ofcourse I forget to unmount before the shuttown and let it mess with my drive again. I've lost so much time and some data on this issue. It is absolutely unacceptable and infuriating to release update like this... But if it's by design that is disgustingily outrages eneough for me to ditch the entire Apple ecosystem whatsoever. It doesn't seem to be the software up to any proffesional standards.

Having the same issue with external USB drives, USB sticks and external keyboards that are connected through USB on macOS Sonoma 14.2 and MacBook M3 Pro.

Some of my external keyboards are only working if I connect it through a USB A_C cable having a USB C adapter on the USB A end of the cable.

I haven't been able to connect none of my external SSDs though, tried like a bunch of USB cables, USB ports on the MacBook.

I think I exhausted every avenue I can think of: 

The external SSD shows up as a USB device in System Reports, but doesn't show up in Disk Utility. It's a pretty bug tell that it's a hardware issue if it doesn't show in Disk Utility.

I also tried to run the Apple Diagnostics program, but it did not return any errors.

Tried setting up a test user account with the default settings, the drive does not show.

Tried to see if the drive can be read in Safe Mode, but nothing.

One interesting thing are my external keyboards which are HID devices. USB C_C cable connects them then automatically disconnects it. USB A_C connects to some of it fine, depending on the controller used in the keyboard's hardware.

Currently talking to Apple support to see if they can fix the issue, but I don't have any hope.

This is 100% definitely crystal clear that an issue with macOS Sonoma. This thread (and others) proof that it's not a isolated issue.

Sonoma seems to have issues with Mac OS Extended (Journaled) formatted drives as well. I was using a high-speed 1-TB SSD as an external drive hosting the home folders (2023 Mac Mini M2, 16GB Ram, 256GB SSD). Worked perfectly until Sonoma. Sonoma seems to be designed to force people to use Mac-only software and hardware. Sucks for those of us with fixed storage on their systems. I've spent more than six hours troubleshooting with senior-level Mac support with no fix in sight. They've escalated to the engineering team. We'll see if they can do any better. Beginning to regret my Mac mini purchase.

Still 14.2 has not fixed the issue with external hard drives in ExFAT

I'm going to post this again as it looks like my prior post was deleted.

I have M3 MacBook Pro. (AUD$4,800+) Worked fine with my LaCie 5TB rugged until Sonoma. Once I installed Sonoma it stopped recognizing it. As in immediately stopped working. Worked the minute before Sonoma. Did not work after Sonoma.

I spent a full Saturday on the phone with an Apple Engineer doing every single different thing to my computer - and they told me they could not figure it out. Recommended I get data recovery to try and save my files.

With no other options I purchased another new LaCie 8TB d2 professional directly from Apple ($600AUD). It is formatted exFat. It worked fine for a couple of weeks. Then the exact same happens. The computer completely stops recognizing the external drive.

I spend another full day with Apple Engineers. They ultimately tell me there is no fix and they need to escalate to a team of engineers and it will be several weeks. Still have not heard from them.

Calling them again today. Also have told them about this thread. 14.4 update does NOT fix.

Summary:

I've spent 2 full days over 14 hours on the phone with Apple Engineers.

They've told me they have no fix.

I've also called LaCie and they have told me there is no fix. They offered me a "complementary" data recovery on the 8TB hard drive which I bought less than 2 weeks ago. They would not assist me with the LaCie rugged data recover - that was a "too bad" response. LaCie said the same thing happened when Venture rolled out.

Apple - if you delete this again. I will repost it and I will find every single blog / review of computers / review of drives and paste this exact review over and over again.

I HIGHLY recommend not downloading Sonoma. Also as an FYI...M3s you cannot rollback to prior OS.

[Edited by Moderator]

Thanks for posting this. Unfortunately I too am unable to access any external drives since updating to Sonoma. Very frustrating and hope it is resolved soon. I need that external data.

Hi All,

I just fixed my "external SSD not mounting after upgrade to Sonoma" issue.

I called Apple Support and they walked me through EVERYTHING else that I found here and on other forums, as well as things I knew to try myself. I, myself, am a level 3 support tech, and didn't think of the last TWO things the tech, Dustin, had me try and it fixed the problem.

ITEM 1

1. shut down (not restart)
2. boot into Restore mode

• • as soon as you hear the machine ding indicating it is starting up, press and hold Command+R
  • Hold until apple appears (only 1-3 seconds on my machine)
  • once in restore mode, I already saw the drive blinking indicating it was working

ITEM 2

1. System Settings --> General --> Login Items
2. In the "Open at Login" dialogue box at the top, if there is ANYTHING in there, remove it

• • Sonoma may be finicky on your machine
  • If it is, it will NOT boot the drives FIRST if it sees anything in that dialogue box
  • Instead, it will stop the boot sequence and ensure that those startup items are running
  • And it therefore may not come back around to your drive

These totally did the trick for me. Hope it works for you.

Happy New Year All

I am on macOS Sonoma 14.2.1 and my external 1TB SSD SanDisk drive is now unreadable. This follows the upgrade from Ventura.. my iMac never had issues with the drive until the upgrade two days ago. Drive was formatted ExFat..

Updated to Sonoma on my MacBook Pro M1 and things seemed ok. Then I plugged in both my 'big' RAID drives. exFAT formatted, one is 88TB and the other is 60TB.

I can see them, I can 'open' them but it's missing a couple of main/large folders 14TB worth of data files. The folder just doesn't show. However, the remaining space on the drives 'seem' ok i.e. the 60TB shows 15TB free which is about right so something is there, and the 88TB drive shows ~37TB free, again, it seems thats the right amount of free space. But hitting the > on each folder just drops down and doesn't expand.

Nothing is readable on the Sonoma MacBook M1. and I doubt when My M3 arrives it'll read them either.

I plugged the 88TB drive into my wife's PC and did a 'Scan and Repair' even though Windows said there was no need. Ran it and it said it was ok and I could access everything on my drives.

So, Sonoma, as people have said, has ruined the ability to use these drives until I get another drive,

I'd need one 88TB to copy the 88TB data to, then format the OLD exFAT 88TB and copy the 60TB to that, and then I can format the OLD 60TB and have that for when the other drives fill up.

Oh, follow the link and 'downgrade' back to Ventura and wait to see if Napa? is a better macOS...

/Disappointed in Cupertino...

This actually worked. Have a WD Passport that a backed up my M1, the disk wouldnt eject cleanly no matter what I did. New M3 with Sonoma 14 wouldnt recognize the drive. Plugged it into Windows, did a scan (right click -> properties -> scan/fix tab), said nothing wrong, but then when I plugged into M3 it found the drive.

Good find!

Cannot believe it's April 6th 2024 and still Apple has not corrected this major problem with Sonoma that's been going on for 6 months. I'm a professional photographer & videographer and dropped 2k on one of apples new M3pro computers in January, which is marketed towards people in my profession, and have been having issues mounting my crucial SSD ever since I got the computer, which prevents me from doing my work basically rendering the computer useless to me. Every so often the drive will mount again randomly but if I unplug it or restart my computer then it will not mount again. Currently cannot get it to mount, have tried every troubleshooting idea I've been able to find. The data is recoverable luckily, which I found using Disk Drill, but the drive will not mount to be able to use it. There's no way to install an older OS on these M3 computers. Almost anyone who's buying an M3pro for its intended professional purposes would be using SSDs and running into the same issue. Unbelievable.

I'm having the exact same issue ever since I updated to Sonama. It was so bad it fully corrupted two lacie hard drives, which cost me £320 to repair. I've spoken to apple, I've updated to the new 14.1.2, I have fully factory reset mac, and still causing me stress as it happens often, after ejecting fully. The next day I go to load hard drive, disk utility doesn't load and neither does my drive, have to use 2015 macbook to restore and luckily it does! So frustrated by this, but glad to see it's not just me. I formatted a new harddrive to mac only and that's of course working fine!

I have a pretty much state of the art 2023 Mac Mini M2 8G ram, 256 internal, and a 2T external SSD FORMATTED in APFS since day 1. The computer came with Ventura installed and the SSD worked perfect! Then I recently migrated to Sonoma 14.2.1 and the external ssd drive disappeared after rebooting, never to be seen again by Sonoma. WTF?  

I tried all the tricks and still no external ssd to be found. 

It is an outrage that the recent update Sonoma 14.3 does not correct this critical flaw!

Out of frustration, I concluded that Sonoma sucks and I restored Ventura as follows:

On a Mac with Apple silicon your computer must be connected to the internet. If you’re reinstalling on a Mac laptop, plug in the power adapter.

1. Shut Down your Mac, press and hold the power button until “Loading startup options” appears, select Options, click Continue, then use Disk Utility in the Recovery Window to initialize your drive APFS, which wipes it clean.
2. Then, In the Recovery app window, select Reinstall for your macOS release, click Continue, then follow the onscreen instructions. 

After I reinstalled Ventura, I restored the most recent Time Machine backup, which was only 2 days old. Being very grateful that all my precious data had not been chewed up and destroyed by Sonoma as some have reported happened to their external drives data. Did I mention that my Time Machine is on the external SSD?

I’m happy to be back with Ventura. For me, there is absolutely nothing compelling about Sonoma that warrants having to put up with any hassles with it.