Sequoia 15.0 bugs - external hard drives

Hello, I’d just like to confirm the mention of “ext4” not being compatible with Sequoia. Would this be for locally connected drives or all drives i.e NAS? The reason I’m bringing this up is that Synology suggests that “EXT4 is for speed, NTFS for easy compatibility with Windows. Forget about the rest.” I have 16 TB of Synology storage running ext4 connected to my M1 MacBook Pro running Sonoma with no issues. Just looking down before I step in it.

I had the same issue with older USB-A spinning standalone hard drives (SSD hard drive and plugged in/powered USB drive both worked).

What ended up working for me was to go to System Settings > Privacy and Security and then "Allow Accessories to Connect" where I changed it to "Always". The drives then showed up. Perhaps something with the USB accessories security setting that was shutting down USB power?

Year after year, even after previously fixed, I have had the same problems with Time Machine and inability to write to external SSDs.

I have posted over and over, year after year, yet never a permanent solution, there must be no profit to be made by actually solving it.

I am glad to hear that you found solutions for your problem. However, none of them apply to any of my years-long, recurring external drive mounting issues. Which year after year appear to be solved via an OS update only, later, to be resurrected with each new operating system. That’s software engineering.

I want to add my voice to this.

Since updating to Sequoia in November, 2024, neither of my external USB-C drives have functioned normally: spontaneously unmounting; Photos (my library lives on an external drive) having to quit, rebuild or restore from iCloud; Time Machine backups via USB-C taking FOUR HOURS to complete, even when no files have been changed or added.

But the kicker is that since these problems began in December I've had EIGHT kernal panics, including three in the last 24 hours. I thought it might be an incompatability issue with the external drives' HFS+ journaled extended file systems vs. APFS, so I chucked five years of Time Machine backups, and erased and reformattted the Time Machine drive to to APFS—and halfway through the first backup the process simply quit, and then crashed my iMac simultaneously, too.

I've run Diagnositcs ("No issues found"), and started up in Safe mode. I've reset the SMC and zapped the PRAM. I ran EtreCheck, and it was clean. The only thing I can think of is that something is causing the OS to not play properly with USB-C. (FYI, the drives are both G Tech G-Drive mobile, 2TB and 4TB.) I've unmounted and put both drives aside to see if the panics continue.

I'm currently backing up—flawlessly—to an ancient Seagate USB 2.0 drive. I can't be sure, of course, but it seems that USB-C is the culprit.

iMac, late 2020 (last Intel model)

Sequoia 15.2

32G RAM

Ok you may be on to something here. I just now realized when we upgraded my Mom's M2 she jumped about 2-3 OS upgrades to Ventura and used Apple's migration tools. My M4 mini jumped from High Sierra on 2011 Macbook Pro to Sequoia. So I almost wonder if starting over from scratch would fix this? I really want that to be a last resort, because I'd have to move all my mail data, fonts and other stuff by hand. But maybe it's old software fighting with new software? I do clean up preferences, caches and preference panes whenever possible. I have my new backup SSD working, so I think I'll give this a shot to see if it works.

After scouring the internet, talking with Apple and OWC, I finally got a powered Hub and my RAID popped right up no issues at all.

So thats the fix id recommend to anyone else who was utterly frustrated by this.

Got a cheap powered 7 port Hub and everything works as it should.

Good luck

I was having disconnects regularly and then I thought I would try an old 10Gbps NVMe enclosure I had spare and so far, 5 days and not a single disconnect. The drive is working fine no matter how much load I put on it.

My ORICO 40Gbps enclosure is the one causing my problems. I don't know if it is some sort of mismatch between the enclosure and the WD NVMe or the ports on the Mac Mini M4 running Sequoia 15.2 just can't handle the transfer speed etc but for now at least everything is working. And oddly enough my other Lacie 1TB SATA drive which is in USB enclosure has also stopped disconnecting. I have not updated the OS since all the problems.

FINALLY FIXED THIS PAIN IN THE *%$£$*

Heres how:

Update to sequoia 15.3.1

Then reset SMC.

Resetting SMC (System Management

Controller)

The SMC controls low-level hardware functions, including:

• Power management (battery issues, random shutdowns)
• Sleep/wake behavior
• Fan speed and thermal management
• LED indicators and display backlight
• External device detection (including SSDs)

How to Reset SMC

For Macs with Apple Silicon (M1/M2/M3)

• Just shut down your Mac and wait 30 seconds before turning it back on.
• SMC resets automatically on startup.

For Intel-based Macs

1. Shut down your Mac.
2. Press and hold Shift + Control + Option +
3. Power button for 10 seconds.
4. Release all keys and turn your Mac back on.

Then Reset NVRAM

Resetting NVRAM (Non-Volatile RAM)

NVRAM stores small but crucial system settings like:

• Startup disk selection
• Sound volume
• Display resolution
• Time zone settings
• Kernel panic logs (sometimes causing crashes)

How to Reset NVRAM

1. Shut down your Mac.
2. Turn it on and immediately press and hold
3. Option + Command + P + R.
4. Keep holding the keys for about 20 seconds.
5. Your Mac will restart, and NVRAM will be reset.

I use Logic Pro and use an SSD and run my projects from it. Every day since updating to sequoia it would eject itself at random times, Logic would crash. Then when I did want to eject my drive it wouldn't do it. Was driving me CRAZY. Hope this helps some of you!

R

Solution for SSDS on M4 Pro: Format external drive to ExFAT, and drives return to normal to normalish speeds.

So I had the same or a similar issue that could be resolved with the Apple Support Team.

Situation: Abysmally slow external SSDs (worst case 8MB/s write) connected directly to USB C port to MacBook Pro 16" M4 Pro but were fast on MacBook Pro 16" Intel?!? My Samsung T7 randomly ejected on my old MacBook but not on my new one!?! Bro idk...😀🥲😭

Hope this might help some of you 🥺

Kindest regards

Stranger on the interwebs

A solution that helped me with SSDS on M4 Pro: Format external drive to ExFAT, and drives return to normal to normalish speeds.

So I had the same or a similar issue that could be resolved with the Apple Support Team.

Situation: Abysmally slow external SSDs (worst case 8MB/s write) connected directly to USB C port to MacBook Pro 16" M4 Pro but were fast on MacBook Pro 16" Intel?!? My Samsung T7 randomly ejected on my old MacBook but not on my new one!?! Bro idk...😀🥲😭

Hope this might help some of you 🥺

Kindest regards

Stranger on the interwebs

I was so hoping my first failed external hard drive would open after upgrading to 15.3.1, but the "invalid node" structure is preventing it from opening. Was hoping for a miracle but it's just a failed HD. The new SanDisk external is working fine.

TLDR; Try a new micro-B USB cable. Seriously, that fixed it for me...

Got a brand new mac mini M4 pro delivered yesterday. Backed up to my time machine on my old iMac. Tried using that in migration assistant on the new mac mini... hmm, that's odd it's not finding the drive when plugged into an apple adapter. Just migrated via wi-fi instead. Plugged the time machine drive back into the old iMac and it was also not mounting. Hmm, I guess it could have gone bad but the timing is very suspect. Plugged it into a PC to check whether the drive was cooked and it was mounting and formatting fine. As a last resort, tried another cable I had laying around and it mounted instantly. It seems to only be an issue with micro-B USB cables, at least anecdotally. If your drive is using micro-B, try or buy another cable and hopefully it fixes your issues. Cheers

Just getting my new iMac set up and connected it to a new external SSD. I erased its contents but when I tried using Time Machine to back up my data to the new SSD it's recognized but there's a red exclamation mark and a popup which says Backup Disk Not Available - try backing up again when SSD is available. I unplugged the SSD, restarted and reconnected the SSD but got the red ! again. Anyone know what this means?

From what I have read, Sequoia does support HFS+, but it is a deprecated format with APFS being the preferred format for all drives and the required format for the boot drive. Sequoia also supports even older formats such as FAT32, not to mention ExFAT. It even supports NTFS for reading, and writing if a third party driver is installed.