Board Thread:Skyrim/@comment-11618741-20150726035340/@comment-1470368-20160225135724

Simple. Don't get the "Paarthurnax" quest in the first place.

I stopped talking to the Blades after getting the Dragon Infusion passive bonus. I didn't even know there was an alternate quest that allows you to decide whether to kill Paarthurnax until 2 years ago.

Nope, I'm never killing Paarthurnax on any save-file.