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

I made same, connect into a Windows, run a Repair and worked in a M2 MacAir

I had some issues with my USB drives (Media & Time Machine) and Ventura earlier this year and one of the steps that Support had me undertake was to format my external drives to APFS. I must say, I've had no problems since but what a pain... Moving forward with Apple, nothing good can come of having drives formatted in ExFAT.

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!

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.

Having the same issues, so every time I connect my outboard drive, I go to System Preferences, then Siri and Spotlight, then to the bottom where "Spotlight Privacy" is tabbed.

Click on Spotlight Privacy, drag your drive in, then hit the "-" sign and it will be recognized and become searchable for that session until you eject it. Not the most elegant solution for a new operating system, @Apple. WTAF? Fix this. Or is it just another attempt to make you spend more money on memory?

Hope (everything but the screed) helps.

HenryMartin wrote:

1. The solution with the brand-new lacie rugged, 4 TB external was to;

delete and remove the “useless seagate” tool kit.

2.

With apple utilities , partition the drive in to 2 partitions. It would not allow me to just directly erase and reformat in to APFS.

3 Now I could erase and reformat the new partition into any APFS.

It didn't have a GUID partition table. That is required for APFS. You could have used the View popup menu to "Show all Devices" and erased the Device, not the mounted volumes. That would also allow you to select GUID Partition Map like the Partition tab allowed.

I recently updated my 2023 Mac mini to Sonoma 14.2.1 from the original OS, Ventura 13.6. My external 2T SSD drive formatted in APFS worked without flaw until I installed Sonoma. My external drive disappeared. I tried multiple recommended fixes to restore access to this drive. All my documents and even my Time Machine are on this external drive! So I went back to Ventura 13.6.3. Pain in the *ss, but it worked. Thankfully, TM backed up a few hours before installing Sonoma, and none of the files on the external drive were corrupted! Reading the complaints in this thread, it seems beyond the pale for Apple to release an OS that does this to 3rd party external drives, drives that were in perfect working order on older versions of the OS. And then offer up as support reformatting the drive! What kind of arrogance is this? I'm lucky to have been able to install a clean Ventura OS and then restore everything from Time Machine. I won't touch Sonoma OS again!

I have an issue with an ExFat Lacie 6big drive on 14.2.1.

During a writing process I got an error, after this event copying files or creating folders became unreliable. Disk aid found and repaired errors, but this did not fix the issue. During backup some folders were unreadable, currently and seemingly non-existent (but formerly existing) folders causing reading errors.

I have been ignoring an error message from Lacie RAID manager software that it can not access removable volumes. When I first saw this I rebooted, reinstalled, rebooted, granted full disk access, rebooted, did everything again, no success, but since disk operations seemed successful I just clicked on “don’t show this message again”.

An even bigger irresponsible act from my side that I also ignored the “not initialised” status of my RAID. It was initialised when I got it 4 years ago, and again, operation seemed fine, initialisation would have removed all my data, and this was just one of a few storages where this data is kept.

I tried with my Macbook (which was never connected to this drive prior these events), same result.

I had no mounting issues. Some data was lost for sure, but maybe a few dozens of GB-s out of 18 TB, and nothing that has no backup.

Seagate/Lacie eventually replaced my drive, since it was under warranty. I just got my replacement, it mounted. It is formatted MacOS journaled, working fine at least for simple file write/read. It is initialised out from the box (the first one was scraping for a week when I started working with it).

The Lacie RAID manager software still throws the error that it can’t access the removable volume. And the same with my Macbook, so this is not device specific from either side.

Seagate blames Apple, Apple gave me an appointment with a senior advisor for tomorrow. Since my iMac Pro is now 5+ years old, well beyond any AppleCare, I think either they know very well that what is wrong, or they don’t exactly know what is wrong, but they are sure that they did something really bad, and they must sort it out.

My conclusion is that buying a 7k iMac Pro and a 6k Lacie 6big does not ensure safety for your professional digital possessions. I am working on genetic sequencing data, and also digital images and videos, that literally cost thousands of work-hours and hundreds of thousands of US dollars. This can be gone in one second on any device. And not just because of material fatigue or physical damage, but because of stupid management rushing software development, and trying to save money on testing and quality control.

As I said before on this forum, I'm using 3TB drives, a couple of them are Apricorn secure drives, one for work and the other a back up. They have trouble loading, but haven't 'failed' and I haven't lost any data (thus far!). To get them to work I run disc repair on Windows (at work). That usually helps. I also try Disc utility on an old Mac with OS<Sonoma (I have two, one works but it takes ages, the other won't work if the drive has already failed to connect in the Sonoma Mac.

Just a question, all my drives are formatted ExFat (purely for Mac/Windows compatibility). Is the problem also happening with Mac formatted drives (apfs)? My only option, as I see it at the moment, is to buy a Windows based laptop from home and wait until such time Apple wants my computer business back. Between the wife and I we are on our seventh or eighth Mac so we are pretty ensconced, but this issue and the failure to rectify it (after a number of updates) may be a dealbreaker?

Update; 4 march 2024. I had been using Disk Utility every time when restarting this Mac Mini (Sonoma 14.3) if I wanted to access my 4TB Western Digital drive or my other drive that I use for back ups (4TB Seagate). However, the most recent time I wanted to back up, I had to step away from the desk just after plugging up the Seagate and came back after a few minutes to find that it had loaded up okay, without running Disk Utility. I then plugged up the Western Digital which didn't immediately load up but again, after a few minutes, it appeared and I could access as normal.

I guess I was just too impatient, or maybe I'm just fortunate, that my drives are now all loading normally as long I give them time.

Not sure this is helpful to anyone, but what worked for me (Lacie usb-c spin-drive, Journaled) was to simply replace the usb-c cable. I´m no expert by any means, but suppose these cables have different voltage capacity, bandwith or something. The previous two cables would allow the drive to show up in the Finder but wouldn´t allow me to either view or access any files.

Strangely enough, when connecting the drive directly to my iPhone 15 Pro Max, any usb-c cable worked without issue and the files showed up immediately?

Moving all files to the laptop then I´ll convert the external drive file system to APFS, which seems to be a general

recommendation when not using the drive across different platforms.

Photographer here! I had the exact same issue when I upgrade to Sonoma. I would HIGHLY recommend download NTFS for Mac. It's a free program that has at least allowed me to be able to mount my externals and work off them in Lightroom and Photoshop. I'm unable to create new folders or move things around on some of my externals when mounted, however, it does allow me to move the files onto new externals so the data is not lost.

[Edited by Moderator]

Boot in MacOS Recovery And mount The drive in Disk Utility app or create a new local account on Mac and login this account to access the external drives.

Got my drive functionality back by reverting to mac os ventura thank god

A powered USB hub seems to be a good solution. On my 2021 iMac I've been successful using the more highly powered usb connector on the back of the computer. Try different ports if you can.