[BUG] Unreal Editor 4.2.1: "Light Build Failed. Swarm failed to kick off." Win8.1

While building the ligths regardless the project i pick…Any idea?

You’ve already posted this on AnswerHub(which is the place to get help on crashes and bugs) so i’m closing this thread now.

Also, give more information on your computer specs, crash log, etc. on the Answerhub post please.