Just found it in a reddit link (https://www.reddit.com/r/Vive/comments/6qroqi/vive_tracker_role_changer/), it is an exe that asks to connect the Tracker to change it to a controller… is that right? I can turn it back to a tracker after that?
I also found out where the Unreal code is crashing (Editor crashes with Vive trackers. - XR Development - Unreal Engine Forums)… Downloding Unreal again to try this fix…