There's a lot going on here.
** (gedit:6811): WARNING **: 09:43:16.405: Set document metadata failed: Setting attribute metadata::gedit-spell-language not supported
I suspect you got this warning because you used sudo to invoke gedit. If you want to use sudo to invoke an application with a gui like gedit add a
switch like this:
when I logged out of my account, my wife's name was not shown on the login screen as an available user account!!
Um ... I have no idea about how that happened but I'd bet real money it had nothing to do with Sir Charles'
suggestion of adding the user option to your fstab line.
All I can tell you is if you really just installed Mint (
I just installed Linux Mint 64-bit v19.2 with a separate DATA partition.
) I would just start over again.
When you do have the installer mount this partition to /mnt/DATA to begin with - not /Mnt/DATA, or /Mnt, or /mnt - but /mnt/DATA.