External SSD keeps disconnecting after upgrading to Sonoma

Disk not ejected properly:

This can be caused by a shortcoming of your external Bus Powered drive, and not of your Macintosh computer.

When you Mount any ejectable drive, the Directory from the drive is copied into RAM, and the directory on the drive is marked status = checked out (like a library book that has been borrowed from the lending library). The RAM copy is considered the Master copy, and changes that you make while working are made in the RAM copy of the Directory.

When you Eject/UnMount a drive, the RAM copy of the Directory replaces the copy on the drive, and the status of the directory on the drive is marked status = checked IN and Good.

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Some external drives get all their power from the USB Bus. Bus-powered external drives should gracefully transition into standby and accept reduced USB power supplied when your Mac sleeps.

Some drives do this perfectly. Other drives do not transition gracefully and do not run only on standby power. Instead of stand-by, these drives disconnect. The problem is, the Directory from the drive has been checked out, and the Master copy in RAM has no way to get back to the disconnected drive.

Some Time later, when your Mac wakes up again, the drive reports 'I just woke up and am ready to connect'. Your Mac is confused because the drive will not CONTINUE from where it left off, so the Mac says "drive disconnected". The copy of the Directory on the Drive is Stale/checked out (not the Master copy). You get the messages "drive not ejected properly" the same as if you had pulled the cables out while running. The correct state of the Directory can not be determined instantly, but requires Disk Utility 'Repair Disk' procedure.

Summary: this is likely a deficit of the DRIVE, not the Mac. If any one of:

• the drive had external power -OR-

• the drive transitioned gracefully to standby -OR-

• the Mac did not sleep, THEN...

...this would likely not occur.

Complete wrong, its disconnects when Mac is awake and disconnect drive when copy process going. Also, this drives very well working before sonoma and very interesting it normally work on Linux and Win stations without any issues with sleep, power of bla bla bla etc.

Any update when we will get a fix for Sonoma? Currently I can't plug any external APFS external NVMe drive to my M1 MacBook Sonoma. It can disconnect in any moment and corrupt the file system.

Mac won't recognize the external drive after sudden disconnect, and Diskutil can't repair the APFS container. Yes I have tried every possible command in terminal.

Update: Later same afternoon, Lexar 128 GB USB flash drive became corrupted. Unable to connect, much less repair, with Disk Utility (permanent beach ball). This same Lexar worked fine many times on my old Mojave system. I did a few tests with smaller, newer 4 GB and 32 GB USB flash drives and had no problems, so I can't rule out that the Lexar went bad. But I see there are other reports of disks being corrupted while attempting to use with Sonoma. So, backup your external media early and often with Sonoma!

Mee Too'  What's going on with Apple? My hard drives, Lacie 2T and G Tech Hard 4T drives, keep disconnecting and reconnecting. It's a nightmare since I upgraded to Sonoma 14.4' what they playing at!!!!!!

It started happening for me too. It happened two times in a week, but only if I `rsync` from the SSD to a `smb` target. Might be a coincidence, but it never happened before. I am using a WD Elements SE SSD. Not sure, which formfactor it has though.

I have had good luck resolving this with Jettison from St. Clair Software.

https://stclairsoft.com/Jettison/

I was disappointed I had to install something for a function that should be native to Mac OS, but time is money and the small cost was more than worth it.

Good luck.

I initially thought the same about my SanDisk Portable Extreme and returned it, but had exactly the same issue with both the replacement and all my other drives (la Cie and OWC, Samsung... I also previously returned the Samsung thinking it was faulty and and replaced it with the first San Disk). I was on Monterey at the time and lost a lot of data due to corruption, and a fried disk. The problem was initially resolved by changing the Thunderbolt ports on the MBP. However, it returned a few months later, so the logic board was changed and o/s upgraded to Ventura. That didn't cure it either.

Most people seem convinced it's Sonoma, but not in my case. What mac do you have? In case yr using an Intel, it's recently been suggested to me it may be a known issue with the i9 processor.

With Sonoma 14.4.1, I think I have now had external HDD disconnect twice about a week apart. Two different HDD, two different cables, two different ports on my MacBook Pro M3 Pro. This occurred while running Chronosync to backup my internal SSD. Chronosync would run for 7-15 min, then quit with errors. After unplugging the HDD cable, re-connecting it, and re-running Chronosync, backup was completed.

‘...it's likely a deficit of the DRIVE, not the Mac.’

Trying to get my head around this. If this is the case, I’d like to understand why it would be no problem for 18 months, then gradually start to happen on ALL external drives (some own power, some not), first on one port, then on another, then stop being an issue - for a few months - when all the ports were replaced, only to gradually reappear, again on all drives, including a brand new one, replaced after the repeated false ejections fried one drive. Disk Utility didn’t help, data corrupted, and another drive eventually fried too, as did the port on an expensive external monitor.

After a year of misery on Monterrey, then Ventura, I finally got a new Mac. It’s running Sonoma. Fingers X’d.

For me this happens so rarely (about once a month) that I still haven't ruled out the possibility, if my Thunderbolt port might be damaged. Is there any kind of USB log that shows connects and disconnects of USB devices?

in my case with external HDD (USB powered WD passport and also a Thunderbolt RAID with power adaptor) I always had "put hard disk to sleep" off. And they both got suddenly disconnected daily.

Until recently I also had them all formatted as MacOS journaled.

Since I changed them to APSF and set "put hard disk to sleep" ON, I did not note disconnections anymore.

But of course you are all talking about SSD here and supposedly have them APSF formatted already, so that can not be it.

Also having the same issue! Noticed it on both my 2023 Mac mini with a 3 disk traditional spinning hard drive configured as RAID 0 (using disk utility), and on my 2021 MacBook Pro with a Crucial X6 SSD.

I have the same issue with a Samsung T7 1TB drive. I have noticed a pattern. I have three portable usb drives(2 SSD and one Lacie rugged).

All drives except the Samsung T7 work perfectly on all my Macs (+ others where I work).

The T7 works on all macs that have earlier operating systems (not Ventura or Sonoma). On operating systems from Mavericks to Monterey The T7 works fine and in the system report in the Hardware: USB tab, current available is 900mA and current required is 896mA. But on either Ventura or Sonoma, current available is 500mA and current required is 500mA. The other drives (WD passport 1TB and Lacie Rugged 2TB) show current available is 900mA and current required is 896mA across all hardware and operating systems.

The T7 will mount but after a short period will become unresponsive and be difficult to eject. When I first noticed this the drive would eject itself but it no longer does this. It just becomes unresponsive. I have seen it happen on four different machines, two with Ventura and two with Sonoma. I hope Apple will take this issue seriously.

Perhaps this is difficult to follow so I will summarise:

WD passport and Lacie Rugged work on Macbook Pro M2 13.6.7, IMac M1 14.4.1, IMac M1 13.6.6

Samsung T7 does not work on Macbook Pro M2 13.6.7, IMac M1 14.4.1, IMac M1 13.6.6 but works perfectly on a variety of hardware up to Monterey.

When T7 has problems current available is 500mA and current required is 500mA and this only happens with Ventura and Sonoma

I suggest you run first aid on the drive. If that fails to fix the problem, erase and reformat the drive.