Drive won't mount through disks, Ubuntu UI, or on reboot, but will mount with terminal command

I have one drive that refuses to mount on reboot or when you manually click the mount button through the Ubuntu UI or Disks Utility. But if I run sudo mount /dev/sdn /media/user/Storage31, it mounts as expected until the next reboot.

I can fix the GUI mounting problem if I change the folder path that it mounts to /media/user/Storage311. There are no other programs or drives using the path /media/user/Storage31 currently, and I can see an empty folder being created there each time the GUI attempts to mount the drive.

The only thing that's changed since this was last working was the drive was reformatted. However, I reformatted many drives that day, and this is the only one that started to have problems.

Obviously the easy solution is to just change the folder path to /media/user/Storage311 and call it good -- but WHY? What's preventing me from using this specific folder in the GUI, while the terminal command mounts it to that point with no issues?

Solution 1:

As per Arthur's advice, I checked the contents of /etc/fstab and found a couple of weird entries for that specific folder path (/media/user/Storage31). I deleted them, rebooted, and now the drive mounts properly through the GUI.