External SSD keeps disconnecting after upgrading to Sonoma

Drives like the MyBook came with software, and the manufacturer suggested you install that software.

What that software does is to "spare you the annoyance of having to re-initialize the drive" from its factory set Windows New Technology File System (NTFS, the W is silent because there are no other Operating Systems) or similar unusual (on a Mac) format. Instead, the software they provided would simulate a MacOS drive inside an NTFS file for your Mac.

The downside of using the manufacturer's software is that if the manufacturer's software is not loaded, the Macintosh Volume may not be readable, or may not be writable. This means that in startup manager, Installer, and in Recovery such as after a data loss, the Macintosh Volume may not be visible.

The standard advice given here to all users, including novice users, is to discard the manufacturers software and NEVER use it. "Best Practice" is to erase the physical device when new, using only MacOS Disk Utility, and create the fundamental data structures needed for consistent, reliable use by MacOS.

Be sure to "show all devices" which will allow you to ERASE the entire Physical Device by its immutable manufacturer-given device-name, not just user created Volume-name such as ‘Macintosh HD’.

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The litmus test for 'what format is that drive' is to run this Terminal command, and look for the NAME of your drive in the list. This is the output for an Apple File system drive, first for the (Physical), then for the (synthesized) APFS container-scheme:

diskutil list

...
/dev/disk6 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *240.1 GB   disk6
   1:                        EFI ⁨EFI⁩                     209.7 MB   disk6s1
   2:                 Apple_APFS ⁨Container disk7⁩         239.8 GB   disk6s2

/dev/disk7 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +239.8 GB   disk7
                                 Physical Store disk6s2
   1:                APFS Volume ⁨X14-SSD240⁩              97.5 GB    disk7s1
   2:                APFS Volume ⁨Preboot⁩                 26.5 MB    disk7s2
   3:                APFS Volume ⁨Recovery⁩                507.6 MB   disk7s3
   4:                APFS Volume ⁨VM⁩                      20.5 KB    disk7s4

my MacOS volume named X14-SSD240 is on a physical SSD drive about 240 GB in size.

Update: I was having this same Issue with my fairly new Kingston XS2000. I chatted with Apple support and opened a case. We tried a few basic things and the drive kept failing to run First Aid. I ended up backing up the drive and reformatting it. Since then I have had zero disconnects. It seems like the drive got corrupted in some way when I did the OS upgrade to Sonoma. I bought this drive new while on Ventura so this is the first OS upgrade. It was annoying to have to reformat a 4TB drive but in the end fixed things.

Same thing for me with an external HDD used for backups. No issue until I upgraded to Sonoma, no issues during the day when the machine is in use, but at night multiple improper disconnect messages. Interestingly, the problem goes away if I connect the drive directly to one of my laptop's USB-C ports with an Apple USB-A to USB-C adapter. (previously I've had it connected to a Thunderbolt dock along with other peripherals.) I've tried different docks and the problem always exists if the drive is not directly connected.

Also, even if the drive is unmounted in the evening, the message still pops up. This suggests that the hub/dock is getting powered down, then powered back up, which would cause the Mac to 'see' the drive and remount it, then improperly disconnect on the next power down.

Before 8 Dec 23, I had Mac OS Ventura and things were smooth between my External NVME drive and my Mac mini m2 pro. But as soon as I upgraded it to Sonoma things between my drive and machine went bad.

My external Nvme drive keeps getting ejected automatically, at start I thought I may have moved the enclosure, but it was happening again and again.

Steps to confirm its the bad update about thunderbolt port in SONOMA.

• I remove the drive and connect it to my old macbook pro (2012) using USB-A cable, and its working.
• I then connect the drive again to my M2 pro mac mini with usb c to usb c cable , but its getting disconnected. I tried restarting also but its same.
• I then connect drive to USB 3 port on My mac mini using USB -A cable and its working fine. I dont know what speeds I am getting on it.

So conclusion, its definitely something wrong with the Sonoma update about handling power or data on thunderbolt ports (I tried on 2 different ports ).

So I will be using the drive on USB 3.0 port until they resolve the issue in next updates , hope so.

I had been using a Mac Mini w Intel processor sunning Sonoma and 5 HD's (3- 3.5" and 1-2.5" portable , all SeaGate, AND 1 2TB SanDisk SSD. One HD was periodically unmounting. Ran TechTools and confirmed it was dying, so discarded it. All the rest were operating fine including an 8TB Time Machine Backup drive.

I then upgraded to a MacBook M3 Pro Max. Migration was a pain. It would not connect to my MacMini, so, I chose to migrate from the Time Machine backup. This when smoothly.

Then I connected my other drives. Soon, there were reported problems with ALL drive! Time Machine could not backup to the Time Machine HD. It reported that it didn't have permission. The other drives continuously got the Improper removal message. The SSD gave a message that it could not be repaired (never asked it to be repaired), that I could copy files from the SSD, but could not alter them

All drives were formatted in the MacOS Extended Journaled format. Connecting the 3.5" drives would take 10-20 minutes topper in the finder. Connecting the 2.5' Portable HD connected quickly, but them started reporting improper removals. The SSD mounted quickly, but with the aforementioned error message.

Spent two sessions with online Apple Support, reinstalled the MacOS Sonoma, removed all potential interfering software (Sophos Antivirus, PIA VPN, TechTools, etc), then went to the Genius Bar.

They confirmed everything I've reported, with no solution.

In frustration, I purchased a LeCie HD in the Apple Store, reformatted it to APFS, and it mounted immediately. So, I went home, set the LaCie drive as my new Time Machine drive, backed up my MacBook.

I've now spend a few days trying to solve the remaining problems. The original TM backup file could not be copied from the original drive to the new TM drive. Eventually I had to give up and reformat the old TM drive to APFS, losing years backups. BUT, that drive has been performing flawlessly for 3 plus days now. I transferred files from problematic drive to the recently reformatted drives, then reprobated to problematic drive , then repeated the problem with the ned problematic drive. Each time a drive was formatted, it instantly mounted when connected to the MB Pro. BTW, the SanDisk SSD could NOT be formatted to the APFS format, but was reformatted to macOS Extended and is also working just fine.

Fingers crossed...

I've been experiencing disconnects of my Sabrent Thunderbolt dual NVMe enclosure (Mac mini M2 Pro, Sonoma 14.2.1). As strange as this may sound, my problem seems to be related to wifi. I use a wired network connection and keep wifi turned on (but not connected to an SSID) only to allow my Apple Watch to unlock the computer. So far while wifi is turned off, I have not had a disconnect. However, the act of turning wifi back on causes the drives to disconnect. This is repeatable behavior. Whether it applies to anyone else's situation I'm not sure, but it might be worth checking to see if it is a workaround if you are facing this issue.

Can You tell more information about this, which FS, if this is NVME M2. Because for me this still not work if FS is ExFAT and M2 device and direct connection to USB. I have some solution, but it works slow, use connection via USB HUB. First initialisation of disk took about 8-10 min but work without disconnections. Kingston Fury 4TB + Anker USB\HDMI HUB.

Do do do report it!

• Official Apple Support
  • Easy route: Get Support > Start Now (bottom of page) > pick device > Live Chat. This has proven efficient lately in my experience. 💡Insist on MAC support or (again, my exp) even when Mac specified, you can waste time with a generalist or iOS person who has no knowledge of Mac or Mac O/S.
  • Why bother*? Because if it continues 2-3 times a week you may end up with corrupted data and fried drives (as I did). Also not a bad idea to get it logged early on so there's a record with Apple in case it becomes a major issue requiring hardware intervention.
• Product Feedback - Apple (no replies there, just for the record).

*Wish I'd reported it so as soon as the problem arose, insead of thinking it was everything but my MBP and losing a screen and 2 disks. Genius Bar was unable to replicate it, so the tech leaned towards the idea that it wasn't a Mac fault. The Mac was finally replaced, but it was a long battle that cost me dearly in time, data loss, stress and hardware.

As others have said, Apple will only take this seriously if they receive numerous reports about it.

For me connecting ssd drive on usb 3.0 port with USB-A connection is working fine.

The problem is with the thunderbolt usb c type port when we upgrade 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.

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.

Same problem with Sonoma 14.3.1 on a new (Nov 2023) MacBook Pro M3 Pro Silicon. Happened infrequently but many times with a 5T external HDD. Tried 3 different cables (USB Micro B to USB A into the USB A female to USB C adapter), happened on all 3 cables. Tried a different 5T HDD, happened with it also. This never happened with either of these same HDD on my old laptop (MacBook Pro mid-2014 with Mojave). Today It has happened a dozen times in one afternoon with a Lexar 128 GB USB flash "thumb" memory stick. I tried 2 different adapters, right and left rear USB-C ports on the laptop, happened multiple times in every configuration. Results suggest to me a bug in Sonoma. When it happens while copying to the Lexar, I get "device disappeared", then a separate alert "not ejected properly".

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

Here's my experience: Since upgrading to Sonoma i have a Samsung T7 not properly ejecting after sleep. This happens on both of my machines: a mini M2 Pro and a Studio M2 Ultra. It happens consistently, regardless of cables and ports used. I also have four (externally powered) Sabrent NVME enclosures, they stay always mounted even after upgrading to Sonoma. Hoping for a fix, because it seems this is an OS issue.

I ran into this problem with my new Crucial SSD that I was using for time machine on my new Studio/ Sonoma. How I solved it was: instead of inserting the cable into a back usb port, I used the front. It no longer disconnects. I have no idea why this worked but maybe this idea will help others.