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.
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.
Try to let us know if all good after that !
Let me know how you get on!
Where is "Always" option in "Allow Accessories to Connect"? Thanks.
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I just updated March 2025 and I have all sorts of problems
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Not sure what changed, other than I did an update. I'm happy to say that my powered hub now works, and other externals seem to be working normally, also.
I have the same issue - I get a fleeting pop up about a new drive and then it disappears. HELP
Update - plugged in a very old USB stick and it detected and read that. Yet not the brand new USB stick I just got or the dictaphone pen I just bought.
My Passport for Mac which I've been using for several years on both iMac and MacBook Pro doesn't recognise my new MacBook Pro (OS Sequoia 15.5). Any advice welcome - thanks.
In my case this is happening with a 2025 M4 Mac Studio that came with Sequoia installed. Unless minor version updates also count as "Sequoia over a previous OS"
Same as above . Sequoia 2021 difficult to connect to. 2016 monterey works fine.
What can be done about this ???
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 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.
Sequoia 15.0 bugs - external hard drives
