an additional stick mounted (stick), then switch to another user, stick is refused becausen "pending action".

An additional stick mounted with user "A", letting stick mounted, then switching to user "B", gives error "one operation open".
After the complete system restart with user "B", stick is mounted, switch to user "C", again error "one operation open".
Best thing would be: automatically take all sicks (if they are any) down and make all sticks after the user switch (if there are any) automatically on.