Sequoia 15.0 bugs - external hard drives

As for resuscitating drives, my fix has been to run the drive through Check Disk tool on my Windows laptop. Fixes whatever errors are on the drive. Of course this only works on FAT or NTFS, eg ExFat drives, which is what my problem drive is formatted.

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

Bad news. I spent several hours at an Apple store yesterday and the outcome isn't pretty. The problem is not Sequoia itself, not power issues, but Sequoia over some previous operating system. I brought to the store 1. my new MBA M2 sequoia, 2. my old MBP Monterey, and 3. my LaCie 8TB drive I'd been using for Time Machine. In the end, they found in the back room a laptop on Seqouia, plugged the drive in...and it mounted no problem. (Apparently this Apple store has kept all their laptops but one on Sonoma. Hmmm.) The best we could come up with is that in all my transitions (2007-2024) from a MB on Leopard to a MBP on Mavericks to a MBP on Mojave to a MBA on Sonoma and now Sequoia, and all the OS updates between, something broke and they don't have a way to find the conflict. Cupertino could fix it. Will they? The only solution I can think of now is to copy all files and applications, wipe my laptop, install Sequoia on the blank laptop, then copy and install all my stuff on the completely new install of Sequoia. Or buy a new desktop drive. Or just use various other drives I have that work to distribute things around. Sitting there in the Apple store with this realization, I felt warmer toward Windows than I have ever felt before. I wish Honda made computers.

I think there's an issue with Sequoia, power management, and micro-B type USB connectors. I tried plugging the drive into a micro-B USB powered hub and it was mounting but was still randomly unmounting unexpectedly. Plugged into a non-powered USB-C hub and no issues so far.

I had the same issue and was successful with the same workaround. That is, upgrading my powerstrip to one with higher power. Apple was befuddled by it all.

Well this worked for me like a charm. I should go to the staples automatically...1. Reset SMC (System Management Controller) - made disk visible. Big relief.

I have had a similar issue where my new MBP 16" (m4) running 15.3.1 would appear to randomly lockup. After several instances I tried various things while it was happening. This is what I noticed:

• External USB keyboard stopped working. (plugged into the only right side USB-C port)
• Wifi and bluetooth appeared to stop working (lost Universal Control to other MBP)
• Wireless mouse stopped working.
• Internal keyboard stopped working.
• Internal trackpad stopped working.
• Power/sleep button still worked.

I examined all logs after the system became responsive again and the only thing I could find was in the wifi.log and referenced the keyboard and usb port the keyboard was plugged into.

Wed Feb 19 16:22:00.852 Usb Host Notification hostNotificationUSBDeviceRemoved USB2.0 Hub seqNum 3026 Total 0
Wed Feb 19 16:22:00.857 Usb Host Notification hostNotificationUSBDeviceInserted USB2.0 Hub isApple N seqNum 3026 Total 1

With that in mind, the next time it happened I immediately unplugged the external keyboard and the problem went away almost immediately. Something about that keyboard was causing the MBP to shut down the USB bus it was plugged into. It appears, since I have not looked deeper, that the internal keyboard, trackpad, and wifi are affected when that bus is shut down.

I have swapped out the cable on the keyboard, and ordered a backup/replacement keyboard just in case. Waiting to see if this happens again. This keyboard while less than a month old did work fine with my previous Intel based MBP (late 2019).

My thoughts are that either newer MBPs are more sensitive to USB power issues, or, something has changed in OS X that makes it handle USB power issues differently. I do hope a software update is able to address this. This is also not the first time I have had a Matias keyboard exibit electrical issues, so this may also be my last one from them.

Advice: Try swapping out cables and keep raising this issue. Also take a look at the wifi.log, since it appears to be the only place where USB issues get reported.

-- Frank

Last night:

Three drives that work fine on my 2016 MBP (on Monterey: too old to upgrade) are not mounting on my New MBA M2 Sequoia. Two Lacie disks ask permission then don't mount. Lacie 8TB asks permission repeatedly but does not mount. Both Lacie drives are several years old. A Seagate just spins for a while with no recognition. Lacie: 8TB powered HDD and 2TB rugged non-powered HDD; Seagate 2TB pocket HDD.

I used MBP to copy drive to drive. I had problems copying data over from one drive to another bc of old format (wrong format. Reformatted on MBP those drives with problems). All are now APFS case sensitive (to accept old files with case sensitive files). All drives, regardless of age or format, mount with no issues on my MBP Monterey.

Today:

Lacie rugged 2TB mounts in Finder and in DU and identifies as APFS. First Aid runs. Unmounting in Finder does not unmount in DU. Formatted on MBA to APFS case sensitive to see whether that fixes the APFS/Mac Journaled weirdness. As it formats the drive, DU says it's formatting to Mac Journaled. When format is done, DU then identifies the drive as APFS. Lacie 8TB still asks permission over and over and does not mount in DU or in FInder. Seagate unchanged--then tried again; see below.

All problem drives continue to mount without issue on MBP Monterey. Seagate also formats on MBP as Mac Journaled then reports as APFS.

Final state: 2 TB Lacie Rugged works. 8TB Lacie powered asks permission but does not mount in DU or Finder. Seagate now mounts without difficulty--I discovered that the USB cable was not pushed fully in. When formatting the Seagate yet again as APFS on MBA, DU reports it is formatting it as Mac Journaled. When format is complete, DU reports it as APFS.

All drives were plugged every time directly into both MBP and MBA. Seagate uses a USB A to USB C adapter. All others are USB C. Somewhere in this mess I followed Apple support instructions to upgrade from Sonoma to Sequoia. But whatever problems I was having on Sequoia happened on Sonoma as well.

Clearly Drive age is a factor. Both the 8TB and 2TB Lacie drives are at least five years old. Seagate is probably older. Power also a factor as the Seagate that mounted in MBP but did not in MBA was only half plugged in at the drive end. When fully plugged in, it mounted immediately.

I'd like to have all of them work, since they do actually work, just not with this MBA on Sequoia. The 8TB is my TM drive. Having just spent over $1k on a MBA, I don't want to buy a new desk drive as well.

A knock wood update:

Since I decomissioned both of my USB-C external drives (one exclusively for Photos, the other for Time Machine backups), I haven't had any kernal panics. None.

As I mentioned above, I am currently using an old Seagate USB 2.0 drive to do Time Machine's dirty work. It backs up hourly with no issues, and in under a minute and a half generally. In other words, it works.

This is, in my opinion, Apple's buggy implementation of USB-C in Sequoia/Sonoma. (Upon reflection, the Time Machine backups taking way too long may have begun in Sonoma.) Likely a software implementation issue, in my opinion. They need to fix this ASAP. (And yes, I have reported the issue to Apple.)

Was reading this morning that HFS+ volumes are not supported in Sequoia.

Perfect. I nearly went and bought another drive. Switching it for a hub to the socket at the rear of the Mac sorted my problem. Thanks.

Maggot wrote:

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

I think it is a power issue. My Mac Mini M4 doesn't have any legacy ports. They are all USB-C/Thunderbolt 4. So even my LaCie 1TB external drive, which I have to connect via a non-powered hub also sometimes disconnects, although not as often as my USB-C drive.

I am going to try a powered hub next and see if that helps but honestly, 2025 and Apple can't sort this out? Crazy!

I've been troubleshooting this, and here's what I've found. (On a Mac mini M4, running Sequoia 15.2; Mediasonic Probox enclosure with 4 bays housing spinning drives and an SSD. Everything stopped working sometime between 15.0 and 15.1.1)

If I run my Probox (JBOD) with just one SSD, it mounts just fine. The moment I add an HDD, everything goes belly-up. Since this is a wall-powered unit, clearly it is not the power drawn that is the problem. I had suspected the interface with the Probox being incompatible with something in Apple's new hardware implementation, but that is now ruled out. What remains is clearly the older drives themselves.

I also have a Seagate 2.5" Expansion HDD which is mounting when connected (it's another matter that the disk is terminally ill). But other 2.5's do not mount when in the Probox, so I don't really know what to make of this bit of info.

I had success ejecting the drive after using AI (Grok) to troubleshoot. Not sure if this is all the issue is but I was able to kill the PID by using terminal commands to get my EHD to eject. This is the process that helped me:

1. Check for Hidden Processes with lsof:

• Open Terminal again.

• Type: sudo lsof | grep /Volumes/DRIVENAME (replace DRIVENAME with the exact name of your external drive as it appears in Finder).

• Enter your admin password when prompted.

• This lists any open files or processes using the drive. If something shows up (e.g., a random app or system process), note the process name or ID (PID), then quit it with sudo kill -9 PID (replace PID with the number).

• Try ejecting again after.

2. Force Unmount:

• If diskutil eject didn’t work earlier, try forcing the unmount:

• In Terminal, type: diskutil unmount force /Volumes/DRIVENAME (again, use the exact drive name).

• This is a stronger nudge than the regular unmount and might override whatever’s locking it.

3. Spotlight or Time Machine Interference:

• If the drive’s being indexed or backed up, macOS can be sneaky about it.

• Disable Spotlight temporarily:

• Go to System Settings > Siri & Spotlight > Spotlight Privacy, drag your external drive into the “Prevent Spotlight from searching” list, and click “Done.” Wait a moment, then try ejecting.

• Check Time Machine:

• System Settings > Time Machine—if it’s mid-backup, pause or skip it, then eject.

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