Sequoia update has caused mounting issues with external hard drives. Ex: had one working and then all of a sudden M3 Max MacBook Pro stops recognizing the device. Now, it won't even find it when it's plugged in. Device works fine on other devices.
In my case, since I installed Sequoia, I can hardly ever eject any flash memory. It always tells me that I can't because they are in use by some other program. I have to force eject or shut down the laptop. With every upgrade I see Apple's quality and confidence drop a lot!
Disk Utility cannot find it. Strange.
The problem is that this menu option no longer exists in Sequoia 15.1.1
Same problems, year after year, especially fall of each year when old bugs continuously resurface. This is Apple, realize that.
Yes! I can verify that this IS a USB problem. Ever since I purchased a new external drive that has a USB hub and interfaces with my new MacbookPro M3 via USB 3.2 I have had issues with the drive not mounting. The drive mounts fine to my older MacbookPro with Intel chip. This is a 2-bay OWC expansion drive with an external power supply. Brand new. And again, it works/worked fine with the older, Intel-based MacbookPro.
In an effort to solve the problem, I upgraded the new MacbookPro to the latest version of Sonoma (it was running Sonoma, as was my Intel MacbookPro) and that seemed to solve the problem...the drive mounted. ONLY THIS LASTED JUST 3 DAYS and then it stopped again.
To make a long story short, I tried all of the safe boot, etc. suggestions and nothing worked. I ultimately (today) upgraded to Sequoia 15.3 figuring that if I took the machine into Apple, they'd demand that anyway. Still no go UNTIL I read this thread, and decided to try connecting the external drive to the MacbookPro via an old USB C to USB 3.0 cable plugged into a dongle that was then connected to the M3 Macbookpro...and IT WORKED. Drives mounted right up and a TimeMachine backup is running. System Info tells me that it believes that I have a USB 2.1 Hub Installed. (see image)
It of course remains to be seen if this continues to work (recall that I did have it working for a few days on Sonoma until it stopped...that was with a USB C 3.2 connection on the drive to USB C on the M3 Macbookpro connection). But there definitely seems to be something going on with this machine and its USB ports (yes, I tried all 3 ports earlier before the current "fix" and none of them allowed the drive to mount).
Downgrading to a USB 2.1 (or presumably older?) connection seems to work. FWIW.
Apple! You have been my "rock" since the 1980's. My rear window carries the apple sticker because I've made a living off of my Apple computers.
I just turned 70...and purchased what may be my last Apple. A new 27" monitor, and a new iMac Studio with plenty of ram to run Adobe software, so I can continue to create graphics, and stay up to date with the OS.
The new iMac started glitching. Bright magenta screen, Adobe programs going blank, having to restart continually. My external used for Time Machine backup was full of older art files as well...so I also worked with an Apple specialist who after hours of investigating (which included re-installing the OS) realized my external was failing. I tried to mount the external to my 2017 iMac with Ventura OS, (which had worked fine for several years) and it will not mount.
However, my new iMac seems to be working fine since removing the external hard drive.
I chalked it up to the external failing. Did some investigating on recovery methods, and it most likely will need to be shipped out at great cost to get those older files off of it.
Last week I purchased a new SanDisk Extreme 2TB for Time Machine backups. It worked for 3 days. I checked it yesterday, and have a new message that says: The disk “My Backup” can’t be unlocked. A problem was detected with the disk that prevents it from being unlocked. Attached is a snapshot of the new external Disk First Aid check.
I have reached out to the Apple technician who is familiar with my former case, and am still waiting to hear from him.
Apple, please give us all an update on this BUG. Steve Jobs would not be happy right now. Neither am I. Apple is costing us money instead of making us money.
I have a new external hard drive which is formatted in the format which only works on mac computers (I can't check what the format is as its not appearing in disk utility or finder)
Is the best option just to downgrade from Sequoia? or will an update be released quite quickly? I have very important data stored on this drive.
My Time Machine external hard drive still works, but my three other external disks (Macintosh formatted disks) do not show up on my desktop or in disk utility. Spent hours on the phone with Apple support - tried most everything with no result. Booted up in safe mode, booted up in test user, restarted several times, disconnect and reconnect the disks, etc. No result. These disks worked fine before Sequoia. Naturally, the Apple technician said it was a hardware issue with the disks - very Microsoft of him. Suspect a software issue.
My Time Machine drive got messed up. I think something happened when the the disk was attached and then crashed the computer. Luckily I was able to retrieve my files from a backup on the Time Machine from the week before. Sedona shows the disk but at this point the drive is unsafe to use. I will stick with Sedona until Mac fixes this problem. Nice to know I’m not the only one having these problems.
Today, 12/19/24 online magazine 9to5Mac released an article about multiple (?) bugs in MacOS Sequoia 15.2 affecting Time Machine, Carbon Copy Cloner, SuperDuper! and possibly other backup utilities.
I use both Time Machine and CCC and can confirm the bugs are much, much older than Sequoia 15.2 (by years).
I suggest you read it. It’s called “MacOS Sequoia 15.2 Backup Bug(s)…” posted 12/19/2024. Good Luck and Merry Christmas!
Same problem for me. Multiple older backup HDDs are not seen by the system, including Disk Utility. My backups are two weeks out of date, as of this message. For me the problem was not linked to an upgrade or a dot version OS update. I bought a new Mac Mini M4 in late November. External drives mounted fine, and both Time Machine and CCC ran normally. Sometime over the evening of Dec. 31, it all stopped. I had been on 15.1.1 for over a month, and was yet to update to 15.2. Why the failure happened without any evident change in the OS is a mystery. Having spent a fair bit on the Mini and monitor/peripherals, I am loath to buy backup disks, so this is missing piece is critical for me.
When it comes to external drives I have trouble mounting, trouble ejecting, and when I'm trying to open a folder with too many files MacOS just says "Loading" for about 10-15 minutes before it even opens the folder. To clarify, the drive works fine on Windows machines so it's clearly a MacOS issue. My best guess is they added or modified some type of cache so now the drive constantly has to access that cache before mounting, before ejecting, and before populating any folder/directory.
I feel your pain. Since, at least, the initial release of macOS Sonoma, I have had nothing but trouble keeping access to my SanDisk USB 3.0 (USB-C) drive. If Time Machine isn’t failing, Disk Utility is.
There have been countless complaints about connection issues (bugs and possible decagon flaws) in macOS with regards to USB-C drives for years now.
Apple appears either incapable or unconcerned about the myriad of issues with macOS and external USB-C devices.
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.
Wish this was a fix, but it's not. (Plus, the instructions for resetting the SMC controller on Intel-based desktops differ from what's posted.)
This bug, which seems to have been around at least since Sonoma, manifests differently across machines, is not confined to any one type of connection/cable and, unfortunately for the purposes of escalation, isn't a global issue.
It is, however, persistent and a major pain. (Note: after 15.3.1, my external drives are now all working, but two of the three—the USB-C drives—will not unmount.)
Yes, it was not the fix. I’ve only had issues with large (5TB) portable drives, Seagate and WD connected via a powered USB hub. Occasionally, the drive disappears especially after a reboot or startup if my Mac Mini M4 Pro has been shut down for some reason. After trialling the SMC and NVRAM fix, the external drive just didn’t show up as connected. My only way to get the drive to reconnect has been to plug the drive into my old 2014 Asus Windows Laptop running W10 and running the Check Disk tool. It always shows there are errors but fixes them and then when I replug back into my Mac Mini, it shows straight away.
Sequoia 15.0 bugs - external hard drives
