just solved another problem that's been nagging me for nearly ever: my main user on Dennis had a different UID than my same-named main user on Nikola - result: files on external drives owned by main user when plugged into one computer, but inaccessible (non-existent user) when plugged into the other computer. combination of groupmod & usermod on Dennis and chown on the NAS where I temporarily plugged in the drives one by one: suddenly this was easy-peasy! and fun! # #