throwaway488933

Recently I was working with a colleague where we encountered a problem that required some troubleshooting. While trying different things we eventually reached an impasse, with multiple of the following:

A: "I'm pretty sure this won't work, I've tried it already. Here let me try it. See, it does't work"

B: "Well, I was reading this article here and it said to try it this way. Maybe you're missing something"

-- Heated argument --

-- Apologies exchanged --

What are some methods/strategies you've used to prevent the -- Heated argument -- phase before it happens?