I have the same problem with the behavior shield. It started after the update to 17.4.2294 (build 17.4.3482.0) It´s not every time I start up my pc but 2 out of 3 upstarts that the behavior shield is not running. I seen several people with the same problem in this forum, is this a bug ? If so hopefully Avast solves this in the near future because it´s quite disturbing to have it this way. And because it gives me a warning that my pc is at risk doesn´t make me feel better.