Partitions show as mounted, no files show in a directory listing

I am stumped here. I have added a new partition to my /etc/fstab

# /dev/sdb2
UUID=3fefb5f5-0477-49b9-bd2d-be5ad8826c03 /mnt/4TB ext4 defaults,noatime 0 0

Before rebooting, I did a mount -a to make sure that it was working, and the partition was mounted. When I did an ls -al /mnt/4TB, I could see all of the files on the partition.

However, after a reboot, I cannot see the files on the mounted partittions.
Doing a mount -av, it shows the partitions as mounted

	robert@ryzen ~ sudo mount -av
	/                        : ignored
	/mnt/4TB                 : already mounted

If I do a mount /mnt/4TB, there are no warnings or errors from the mount command, even though it showed as mounted above. The files are visible

I check the log (journalctl) and it shows that the partition was mounted, and I see no errors

	Feb 01 20:36:08 ryzen systemd[1]: Mounting /mnt/4TB...
	Feb 01 20:36:09 ryzen systemd[1]: Mounted /mnt/4TB.

There are no other messages for /mnt/4TB in the log

Any idea of what the issue could be? Any other information that would help to figure this out?

Maybe the UUID is the wrong one? Note that if you change the fstab, you need also run: systemctl daemon-reload, so that the “fstab-converter” catch your changes.

Let’s say, you mount sdb2 manually without fstab. Systemd knows that it is mounted. When adding a fstab entry and run mount -a, even if unmounting before, systemd remembers your old mount not the one from fstab. Therefore, you need to reload the daemon.

For sure, many things can go wrong when editing fstab.

The first thing I did - after rebuilding my computer - is to delete the old fstab, and then have a new one created using Gnome-disks to set my mounts.

Takes ‘Error 40’ out of the equation.

Please do not use slang idioms. People around the world are here, trying to solve their problems. Do not cause new ones with understanding.

In Danish it is called a Fejl 40, or “Error 40”, indicating that the error was 40 centimetres (16 in) from the device.

Thanks. I did double check the UUID, and copied and pasted it. I also did the daemon-reload each time, but did not document it in my original post.

Your explanation of the process explanation helped make it clear why I was doing it.

Just to be sure, I retested, and the results are still the same. The drive mounts when I do a mount -a after a daemon-reload, and after a reboot, the logs say the partition is mounted, but nothing shows when a do an ls -al.

Thanks for the hint about Gnome Disk. I did not know you could edit /etc/fstab with it.

However, that did not change anything. I removed all of my mounts, and Gnome Disk added one:
/dev/disk/by-uuid/3fefb5f5-0477-49b9-bd2d-be5ad8826c03 /mnt/4TB auto nosuid,nodev,nofail,x-gvfs-show 0 0

The disk still does not mount at boot time. the major change is that Gnome Disks does not use UUID, but the /dev/disk/by-uuid instead.

Any other thoughts?