Linux Mint 21.x cannot auto mount drives of any kind – USB memory formatted FAT32, internal drives iNode formatted drives not already in /etc/fstab — anything that would be automounted to /media/<username>. A modal dialog box opens with the error saying it is “not a folder” and then another modal dialog box that says “Could not display /media/<username>/XXXX-XXXX”
Correction is to change owner of /media/<username> to <username> instead of root.
chown <username>:<username> /media/<username>
I am not seeing any community appropriate to post this, so here it is. If you need to solve this problem on your system, this works. Apparently the automount functionality runs as the user who is logged in, not root, so it cannot add a directory to /media/<username>/