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!
After reformatting my two Time Machine externals, both are working now. Strangely, the crashing of my Photos external drive (Mac OS Extended Journaled), which I decided not to reformat, has also stopped.
That said, the Photos external can't be ejected because some "processes are in use" or something to that effect.
But no more kernal panics or constantly crashing apps. I can live with this.
Since your problem is totally different from the Authors you should start your own topic with details of your Mac, system, drive, etc . as described in this Apple document: Writing an Effective Apple Support Communities Question - Apple Community
That will get responses from those who will be more familiar with that problem then those coming here.
AlWeir wrote:
Was reading this morning that HFS+ volumes are not supported in Sequoia.
According to Apple's documentation, Sequoia supports HFS+.
File system formats available in Disk Utility on Mac - Apple Support (CA)
Tinx_Lvs_JC wrote:
Same problem! Since Sequoia, none of my ports/drives work so can't back up, can't use separate mouse/keyboard, can't use Thunderbolt. Did some research and have attempted everything that is within my ability BUT I can't do anything to do with coding. Apple - please fix this bug! It's a crucial issue.
This is a user-to-user forum. Apple does not monitor the community. If you want to make a report contact Apple through this link: Contact Apple Support
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:
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
Bring up the Info pane for the drive - Control (right) - click and select Get Info. That will tell you what the format is:
If it is an older HFS formatted drive or one formatted in some Linux filesystem (e.g. Btrfs, ext3, ext4) variant, then it won't be recognized by Sequoia.
I've got the same issu with my I Mac and an external HDD. It stopped at 47-48% of the backing or stopped by itself!
Bad news. I'm not able to get a entire Bckup for my puter .
I have same problem with my MacBook Air M1. I recently upgraded to Sequoia and now I get Lacie Hard disk cannot be found.
Same problem, exFAT not working normally, super slow responses
I just updated March 2025 and I have all sorts of problems
Interesting. I have two SSD's running for backups running with Time Machine and CCC (both are Samsung) and have no problem with either app backing up to them since I upgraded to Sequoia. I don't partition my backup drives.
I found this thread when my new M4 Macbook Pro would not recognize an external SSD. Works fine on Ventura on another Macbook Pro. Did not show up on Sequoia 15.1, nor did it show up in Disk Utility. This was the change that fixed it. Changed to Always and immediately it showed up. Plus 1000 for this tip. Thanks!
Edit: I replied to AlWeir who suggested in Settings: Privacy and Security > Allow Accessories to Connect. That was the tip that fixed it. Thanks!
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.
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.
Sequoia 15.0 bugs - external hard drives
