There was no need to unplug, restart, switch off the daemon, nothing... it all just worked. When one time I had a problem changing resolution, whilst it was streaming, and it said the device was in use, I found this useful pi@octopi:/tmp $ fuser /dev/video0 /dev/video0: 437m ...
(~/.config/guvcview2/video0) The configuration file is saved into the $HOME dir when exiting guvcview. If a video device with index > 0, e.g: /dev/video1 is used then the file stored will be named ~/.config/guvcview2/video1 Executing guvcview For instructions on the command li...