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.

Hello! I just received my iMac M3 with OS Sanoma and indeed; my harddrive was working properly for 1 day but all of a sudden I could not see it anymore in Finder.

Luckily, also a Windows machine nearby and all seems to work fine. No harm to the disk. All in FAT32 format so easy to use on both Windows and Mac (normally)

Obviously very curious what Apple will do to make the use of the Intenso 8TB Harddisk possible.

I finally gave up testing my ExFAT external drive. Nothing I could do would cause any corruption in it.

I wrote files, copied files, disconnected it without ejecting, and shut down with it connected.

I would imagine it is either a controller conflict with Sonoma or some other system modification you have installed.

I had high hopes, Ray, but sadly it didn’t work for me. The Thunderbolt SSD will occasionally mount when connected, but still almost immediately disconnects again.

As someone else mentioned, System Information does see that the drive is connected, even when Disk Utility doesn’t see it.

One interesting thing I noticed is that connecting with a cable with Thunderbolt on the drive end and "old-style" USB (2 or 3, I think) on the computer end does mount the drive, but of course it operates only at around 400Mb/s.

It's purely commercial and I have the same probleme :

Apple blocks the use of external drives with premeditation, to market its product. That is to say, if you want more space buy a new MacBook, or trade with Apple. You will give them your old mac, they will give you its price, and you get a new one by paying the difference between the old one and the new laptop of your choice.

As you know, Apple put the SSD and the memory, integrated with the motherboard, so that no one can improve their Mac by only changing its parts. The scam showing up with a tie ;0

Somona is a disgrace. The problem should have been sorted long time ago. Brand new Lacie ssd 4tb takes forever to write Final Cut files. It is not possible to format into any APFS. Giving different 698-- reports.

Apple - be professional and sort it! Look at all the complaints all over the internet!

I also have noticed my USB external THINGS not being happy.

Could NOT use my Scarlett 18i20 on the same HUB that it ran on under Monterey. One would think a NEWER computer and OS would continue to work at LEAST as well as the older one.

Have a 4 bay external drive carrier and it indeed DOES go off into the far reaches of space on occasion...

Fortunately i have not lost data...yet.

Truly frustrated, as are you and i imagine Countless others that Apple just cant seem to get it right!

I'm almost at the point of ........ I run Windows at work and Mac at home and need my working hard drive (and backups) to open on both. The choice is to move from Apple completely. I can't believe Apple are so disingenuous as not to have fixed this already.

I have been reasonably lucky as sometimes it (my Apricorn secure 2TB drive) opens, sometimes not. Sometimes I can see it in Disc Manager, sometimes not. If I do see it, sometimes a 'repair' (up to three hours) will open it, sometimes not. If I run a disc repair on Windows it will open on my Mac, but only once! If I disconnect it (the correct way) it then can't see it if I plug it back in.

Simply not good enough.............

have the same issue since installed Sonoma. Can see the disk in Disk Utility but can't mount it. When trying to unmount, it says it is in use.

If try to run first aid, says "operation failed. Problems were found with the partition map which might prevent booting. Some information was unavailable during internal lookup. : (-69808).

Bought a new HD thinking the old was damaged and have same issue. When rebooting, get a message that says disk can't be read.

I've tried lot of thinks and absolutely nothing works. Can see the disk on NTFS for Mac and on Disk Utility but can't mount it. it's on grey.

This is a total disaster for me. It's on a par with when Microsoft launched Windows Vista. It was so broken I threw it out promising never to go back. And now Mac has come to this. External disks not mounting, not being able to connect usb memory sticks and many friends not able to log in to their bank accounts.

According to Apple's long-standing policy, users do not need to have IT knowledge to operate their equipment and systems. And with this problem, you need not only IT knowledge, but also luck. Maybe Apple expects us to spend another few thousand dollars on new equipment to connect an external drive?

I am having a nightmare trying to access my WD 4TB & 5TB hard drives that were formatted NTFS as I use them on both Windows and Mac - but now they will not mount on the Mac since upgrading to Sonoma 14.2.1 - I normally use Paragon NTFS - the small thumb drives will mount but the larger drives will not. I checked both drives on Windows PC and they are fine. Disk Utility shows they are fine and I got a tick for both, but they will not mount on the Mac. I wish I never upgraded to this horrible operating system - I only did it last week - biggest mistake I have made in a while. Is there any solution yet?

Booting into Safe & Recovery and creating another profile to create a work around may work for some, but not all. Has anyone found the reason for the disks vanishing and the only way to see they are physically connected to the usb ports is via system profile and terminal IOREG. Showing and proving the drive is connected and communicating with the computer but the computer will not acknowledge them.

I cannot get a drive number to force mount or eject, I have spoken to support and the drive manufacturers who finally have asked me to run additional reports and forward it to them in order that it may be escalated.

The exFAT drive I was using suddenly kicked back into life however the Time Machine (APFS) and HFS disk is; is in the ether. I can see it on a PC but a disk repair there doesn't work, so it's just sitting here attached to the iMac and I am hoping for a 'Hail Mary' on getting it work again but as each day and week passes this is becoming more unlikely.

I upload everything to the cloud as a double backup and if I need to use a PC, I can always download the records I'm looking for rather than disk formatting types.

Using a MacBook pro M1 with Sonoma 14.2.1.

LaCie 2big RAID external drive with two partitions. 

One for Time Machine formatted APFS GUID Partition Map and one for storage formatted Mac OS Extended (Journaled) GUID Partition Map.

First partition still there.

Second partition with all my work (3TB) disappeared. Greyed not mounting in Disk Utility even in Recovery mode. 

I was using RAID 1 to avoid such situations. No problem before Sonoma.

Creating another profile not making any difference.

Disk utility says failed repair (-69845) or if trying to mount that volume disenter error (-119930868)

What are the chances of a Sonoma update sorting this out?

This has become something worse than just a nuisance. It affects my ability to get my work done. Upgraded to Sonoma 14.2.1 today - still not possible to read usb memory sticks. If it continues I'll just have to switch operating system.