I have Lubuntu 16.04.2. System boot from Internal HD. User name is 'ale' Everything looks great, so far.
I have connected an External HD named as 'Aquarius'
When boot this EHD is mounted with 'root', since at File Properties at tab Permissions, it says
Owner:root, Group: root
From terminal I run:
sudo chmod -R 777 /mnt/Aquarius
and then I run:
sudo chown -R ale:ale /mnt/Aquarius
but I got the message 'chown changing ownership operation not permitted'