Using Ableton live 12, Guitar rig 7 loads just fine but there is no change to my guitar tone at all. When I go to Settings, there is no Sound option, only Midi so I can't even set or change preferences.
In Ableton you need to create an audio track, select the input where your guitar is plugged in, arm the track and if you want to monitor the guitar + the effect you'll need to either click on in or Auto.