Transmission-daemon keeps resetting

Solution 1:

Transmission daemon re-writes the configuration file with the old options when it exits. To make your changes persist, you need to edit the configuration file without the deamon running. So first:

sudo stop transmission-daemon

Or if you did not install it via Software Center / Official repositories:

sudo killall -HUP transmission-da

Afterwards you can edit settings.json as you would expect and then restart transmission:

sudo start transmission-daemon 

Solution 2:

Edit /var/lib/transmission-daemon/.config/transmission-daemon/settings.json which seems to be file which is copied after every restart of the systemd unit transmission-daemon.service. I didn't find a reference, but a simple test confirms.