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!
My M.2 NVME ssd external drives dropped from 2000MBPS to 120KBPS??? Both of my Macbook pros!!!!! upgrade while transferring a customers information. Now what? "2 days to copy".!!!
[Edited by Moderator]
If there wasn't anything on the external SSD's you needed test drive one by reformatting if Disk Utility can see it. Format it either using this CCC guide or Apples Guide Erase and reformat a storage device in Disk Utility on Mac - Apple Support (CA)
Just make sure that you get Disk Utility to show all devices.
I have a problem where my Mac recognizes the external drive, but the password does not work. I even checked it multiple times from different sources, and one of the sources was the Password Keychain. Has anyone else experienced similar problems?
It is formatted for EX FAT and was working this morning. It just randomly stopped showing up on my Macbook.
The drive still works on other mac and pc.
So strange.
Was reading this morning that HFS+ volumes are not supported in Sequoia.
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.
Someone said that updating to 15.2 sorted the problem. I am on a Mac Mini M4 with Sequoia 15.2 and it hasn't sorted it for me.
Can't tell me that Apple doesn't read these posts. I just got edited.
So.... class action, maybe???
the problem of usb ports and disks is a long-standing issue. especially when inheriting older operating systems. one must also consider that the jump to a new operating system version, which, in my humble opinion, is still quite immature, is never recommended until after at least two minor versions have been released. Taking advantage of new operating systems at launch must be the prerogative of those who do so for testing and evaluation, not for normal use, unless they are aware that there are problems just around the corner or with the specific aim of formulating precise and careful feedback to present to the developer in order for the problems to be resolved.
Having said that, in such cases, I would suggest making a backup of data on an external disk, reinstalling the operating system with a complete reset, even better if to the previous version, and, reinstalling the software by transferring your data.
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?
For me, I did not have a problem with Sonoma or any Mac OS before Sequoia.
I can eject HFS+ journaled external HDs but not APFS or Ex-FAT USB C SSDs - even if I go and force quit everything and restart Finder, Sequoia reports that "an application" is still using the external drive.
This needs to be fixed ASAP.
I have the same problem with my 1TB NVME drives disconnecting from my MacMini M1. I use a USBC case plugged into the Mac or via a powered hub and still the problem persists. Apple sort this as data loss is a critical issue.
Follow-up. Apple was able to help me re-format the SanDisk, which after doing so, the SanDisk did appear on my desktop. We then chose the SanDisk to use for Time Machine auto backups, and this time, Apple had me TURN OFF the "encryption" choice at the time of setting the external up to use for Time Machine.
The external drive has been working for 24 hours, and Apple will follow-up with me tomorrow and then again at a later date.
SanDisk technical support had also suggested it was an encryption error that Apple would need to be notified. All good today! It was ironic that my previous external failed, and the new one failed in the same week but so far so good.
Rob! JUST received notification that you were able to fix your external drive issue with the new Sequoia 15.3.1 update. I am downloading the update right now. I did purchase a new external HD, which also had problems, until, with the help from Apple, we wiped it clean and made it the auto backup for Time Machine WITHOUT "encrypting" it. It's been working great so far. However, I am hoping to be able to launch my failed external HD (since updating to Sequoia OS) that has a lot of my previous graphic jobs on it....Thank you so much for posting! Fingers and toes crossed.
It's never been fixed, just happened to me after install new software Sequoia 15.4 my external hard drive 2TB disappeared till now from my iMac M1, and in the same usb port I connected another USB flash disk, no problem it shows up... it really pain me.
Sequoia 15.0 bugs - external hard drives
