I upgraded ML Agents to 0.6 (which just got released on github) but I'm having this really weird issue with it. Unity Editor does connect the 3DBall example to the training backend, it looks like it starts running and editor itself looks like it's training but training backend actually sits still there. It doesn't consume any CPU and it doesn't give any middle stats on current progress. I got same issue with all the other provided ML Agents examples I tried. Then... here comes the weirdest part: I manually upgraded Puppo from 0.5 to 0.6 and I actually can train and run it with trained brain just fine! (even on 2019.1 alpha) This baffles me, how come Puppo works but no actual ML agent example shipped with 0.6 ML Agents? Edit: figured it out - it was a silly mistake. Examples had actual platforms setup for player and not for the learning brain . It started working after manually swapping them.