I think the reason it doesn’t automatically mount is Linux doesn’t have read-write support for journaled HFS+. It will mount it read only. And it can support read-write mount for HFS+ (journal disabled).
This will list devices, so you know what block device it is. e.g. /dev/sdb1 lsblk -t
This will mount it read only udisksctl mount --block-device /dev/sdb1 --options ro
And in Nautilus you can unmount by “ejecting” it. udisksctl unmount /dev/sdb1
Hey, thanks so much for trying to help me out. udisksctl status doesn’t show anything except my computer’s internal SSD unfortunately… A command like lshw -short to list hardware also does not show the external SSD (There is little chance the SSD is damaged by the way, I bought it a week ago.)
How about sudo blkid? That’ll check every block device for filesystem signatures.
If that doesn’t show anything other than the internal drive, then suggest using journalctl -f and then ‘unplug and plug’ the USB SSD enclosure and see what messages are recorded in the journal. If the kernel doesn’t detect the device, then user space commands won’t matter, and we’ll need to figure out why the kernel isn’t seeing anything.
Indeed, there is no entry in journalctl at all when I unplug and plug in the USB SSD. But it works on my iMac. Or am I missing something really stupid here? You know what, I am gonna check out my BIOS. Something seems fishy here. But thanks a lot for your help!
USB implementations are highly variable, so it might be that the iMac has enough power to drive this USB enclosure, but not the computer you’re plugging it into. It’s surprisingly common to run into inexplicable problems, hence the ideal scenario is to connect via an externally powered hub. This improves reliability significantly.
I am so sorry. Your advice #5 fixed the problem. The SSD mounted automatically and was immediately detected by Nautilus. Your command from #2, however, would provoke the following error message Object /org/freedesktop/UDisks2/block_devices/sda is not a mountable filesystem.