I am a newbie. This is my first animation. I am trying to get a puppet named Caleb to walk. When I added the walk behavior, assuming his handles were all set correctly, he did nothing. I have him in a scene to which I have lip synced a voice track and added several motions and triggered actions. While searching for cues to the walking problem (using his Right Quarter) I changed his mesh from "auto" to "contour" and he disappeared from the scene. Changing back to auto did not bring him back. The scene still plays with his counterpart, Felicia, still visible and both Caleb and Felicia narration can be heard. The timeline shows both character tracks. When I click the “mesh” button in the timeline Caleb’s mesh shows up, just not Caleb.
There are two ways of controlling the walk behavior - the old way where you record "walk left" and "walk right" and a newer "position" based approach. The old way was confusing as it kept walking even when you hit the "stop" button, meaning the character would walk off the edge of the screen. You could get it back, but it was a pretty confusing workflow. So they introduced "position" based instead, where you modify the position value and it walks according to that.
My advice is to flip to position based walking as a first step as that is the most common cause of "where did my puppet go". You then use keyframes to change the position. Or, while debugging, set the speed to zero so you see the legs moving but the puppet does not move.
Then I would go back to Auto/contour etc. Auto picks contour 99% of the time, so I doubt that is the problem itself - you just happened to change that at the same time. I *suspect* it is walking off the edge of the screen (most common reason for the problem you are describing).
If that does not work, come back with more questions. Its easier to sort out one problem at a time sometimes though.