Originally Posted by jedispy
Q: When is the only time that a lightsaber does not cauderize<sp?> a wound?
Do you mean during a fight only? If so, I would say Sidious v Yoda in RotS. Nobody gets hurt because of a lightsaber.
But there are multiple times when the lightsaber is ignited but nobody gets hurt. Some I was thinking of was when Luke ignites his saber and just waves it around for the first time, and when Vader ignites Luke's saber on Endor. And there's also the possibility of, against the Destroyers, when "It's a standoff, let's go" and none of the droids are destroyed, but droids don't suffer wounds.
If you meant during a lightsaber fight, take my first answer.