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

Upon the addition of an external TB4 hub the external drives have become more stable. I am still in the process of reloading my audio samples libraries onto 2TB drive. I'll let everyone know what happens when I finish.

I had the same problem.

I have seen prompt that just blink. I made screenshot and it's say "Allow accessory to connect?" and it was disappeared very quickly.

After Googling, I found solution for me.

Going to Settings->Privacy & Security->Scroll Down->Allow accessories to connect->Set to Automatically When Unlocked.

So, I connected SSD and it works well. After that I switch settings to "Ask for New Accessories" as was before.

I think it's bug in MacOS because disk or MacOS doesn't waiting answer from the user

I hope it helps for somebody

Here we are on March 12, 2024 and a new iteration of Sonoma was released last week, macOS Sonoma 14.4. The big question on this thread is. Does macOS Sonoma 14.4. fix the External Hard Drive connection issue that has plauged so many of us? My external drive problem has mostly been a great inconvenience and waste of time caused by initially upgrading an almost new 2023 Mac Mini M2 from Ventura 13.6.3 to Sonoma 14.2.1. After much frustration trying to get my APFS formatted 2T NVMe external drive to work correctly with Sonoma, I was able to restore my Mac to Ventura 13.6.3. Just like magic, my little 2T drive functioned perfectly again, just as it always had prior to Sonoma. I tried Sonoma again with versions 14.3 and 14.3.3 getting the same old same old with my external H.D.

I am reluctant to clean install Sonoma 14.4. only to again clean install Ventura 13.6.3 and restore settings and files via Time Machine back up to get my H.D. working again. I've become rather proficent and made a routine of upgrading and downgrading Mac OS software because of Sonoma. Why? I expect better than this from Apple.

HAd to power down yesterday... 

Didnt think anything of it as i have had to restart a BUNCH lately..and somehow was devoid of external HD issues...

or so i thought..

Upon the restart of the computer ALL of my external drives were GONE.

Took the USB HUB, mounted on my Monterey machine...NO DRIVES MOUNTING..

Remembered a post about going to Windows , did that and the drives are now back on Sonoma 14.4.

What the heck is going on ?? Unreliable OS that chooses to either see or ignore drives.... 

Come On Apple....

Do not throw your external hard drives out, your information is probably still there. I plugged in my 11yr old mac and my external hard drive still works there, but won't work on my new mac, it's definitely the Sonoma OS. Total Tech told me that Apple is working on a fix, but there was none as of last week.

Well, I also have this problem. There is no solution yet. I share my experience.

Previously: Kingston 2000 2 TB SSD worked on macOS for a year without any problems (and on ventura, and even on sonoma 14.1 for a while), and I also have a 2 TB Trascend HDD. My device - Macbook Pro 16 2021 1 TB. All these external disks were formatted after purchase in the format exFAT (to be available on both Mac and Windows).

A week ago, my SSD Kingston just started falling off, and my MacBook stopped recognizing it. I tried connecting it every now and then, either through a different cable from the HDD drive or through an adapter, but it was unstable—that is, it worked once and then it didn't work again.

1) At first, I thought the problem was with the storage device itself, but on Android, it connected quickly, and the files were transferred perfectly, without any delays. I mean, it works on Android.

2) Windows - I connected a ssd, it is recognized, but gives an error - and windows cannot fix it (as others wrote here that they managed to fix it this way - it didn't work for me) - that is, when connected, I had to choose "continue without checking for errors" and the folders open, but you can't copy them to Windows - it gives an error that the files are damaged. In this case, any file, even a video, even a small text document.

Therefore, it was not possible to extract the data using Windows. It doesn't work correctly (I think it's because of the disk format and MacOS was providing emergency assistance to the disk, so there are no permissions). I remind you that everything worked on the android.

3) MACOS - I have updated to sonoma 14.4.1 - and it doesn't work. The SSD blinks but is not recognized. And now my HDD disk takes a long time to connect - from 5-7 minutes until the Macbook recognizes it (before it was a minute, always!).

I restarted the system from safe boot mode via text support, and it also doesn't see the disk, but after restarting in normal mode, it recognized the disk once. In this way, I managed to copy the files to my disk. But the Finder started to freeze. And yes, after restarting, nothing works again. I repeated the event through this boot, then a normal reboot - and again the ssd started for one time. After disconnecting and reconnecting, it is no longer recognized. Emergency assistance is not provided - it also freezes, and the disk utility sometimes loads, sometimes not. In general, it doesn't work!

4) I tried to connect this SSD to my friend's MacBook, which has an old version of MACOS (9th or something), and it doesn't recognize it either.

....

So I don't know what kind of trouble it is, but looking at the stories of others, I'm sad that after spending a lot of money on equipment and disks, I can't work and it's not fixed by updating the system... Moreover, it happened suddenly and not even after the update, but until then it had been working for a year without complaints.

this has been incredibly frustating to me too! I have a samsung T7 SSD and noticed that my mac would not reliably read it after upgrading to sonoma software. I couldn't think of any other changes, but did not suspect that a software upgrade would have caused this problem. After reading several forums, I am shocked that this is a common issue from a macOS software UPGRADE. it's embarassing that apple pushed an upgrade that created problems rather than solving them.

Nowadays, I just plug in my ssd and wait 30-40 minutes for it to randomly show up on my homescreen...

the same drive is immediately recognized by windows systems.

My Apple M3 Sonoma 14.2 is only two months old.

I'm very lucky that I had copied out my photos (I'm a photographer) before my SD card files were deleted or became unreadable. I don't remember exactly what happened, but suddenly the card couldn't be read and all the files were gone, even my Canon camera couldn't access them.

I don't recall the exact error message I received after the files were deleted or became unreadable.

Now, I'm hesitant to find a way to connect my old 1TB external hard drive because I'm afraid a similar issue might occur, causing me to lose all my old files. This external hard drive cannot be read now ...

This topic is quite extensive here, and there is no solution despite many trials & erros and different approaches on the troubleshooting. The end game is, Sonoma OS is blocking the external SSD´s. My understanding is that Apple is conducting a study to see the conversion rate towards iCloud storage, and consequently revenue impacts. Later a fix will come or not come, but the "pilot project" will be done already and soon, only iCloud storage. Im really considering moving out of Apple ecosystem due their dominant position forcing users into higher ARPU. Really sad and disappointed. Have more than 6Tb in backups, family pics and videos, corporate assets than I´ve being forced to stop accessing by Apple. Incredible !

Am I missing a step somewhere?

I think you are missing all of them: Create a bootable installer - Apple Support

Once the installer downloads, it will try to run, but you can't install an older version over the top of a newer. Quit the installer and follow the steps to create a bootable installer.

Also, Apple started to remove negative comments on this thread. At least they are aware of the issues.

feketegy wrote:

Also, Apple started to remove negative comments on this thread. At least they are aware of the issues.

The moderators aren’t software engineers.

Exactly, and I mean really EXACTLY same behavior, I'm using windows to "fix" external drives to be used on mac again.. you wrote on 24 oct.. today is 14 Mar.. Thanks Apple.

No. It did not.

updated to 14.4.1 and it does not fix. I don't know what to do. I have 4 5T and I can't read any of them