This tool is deceptively simple looking and incredibly easy to get wrong.
Answer "There was some reason in the some place that caused the fault/mistake/problem/error"
Why did the presentation not work properly at the event?
-> It was an MS Powerpoint 2010 version file and the computer was running MS Powerpoint 2000.
Step 2: Ask "Why was there that reason in that place?"
Answer "There was something underlying that reason in some underlying place"
Why did Daryl try to present his newer version on an older version computer?
-> His laptop did not work with the room's projector
Step 3: Repeat another 3 times to get to 5 Levels.
Why did his laptop not work with the room's projector?
Daryl's laptop's video outputs were not compatible with the projector's inputs
Step 4: E.g.
Why did Daryl not have a converter with him?
Daryl did not call the venue in advance to check the supported interfaces
Step 5: E.g.
Why did Daryl not call the venue in advance?
Daryl was too busy and forgot
Too busy to ensure a professional presentation? I think we need a new procedure ... but will it be about company employees who present at public events or will it be about company employees who are working on projects that are forced to work in crisis mode? Or...?
And I can imagine an alternate Step 3
A.Step 3: E.g.
Why did Daryl not export his newer file to the older format to run the presentation on the older computer?
Daryl was running late and too stressed to remember this feature existed
A.Step 4: E.g.
Why was Daryl running late?
Daryl left the office late
A.Step 5: E.g.
Why did Daryl leave the office late?
Daryl was doing some urgent project work that caused him to leave late
Perhaps we need those possible procedures above. Perhaps Daryl needs some management mentoring/coaching on his time management skills or his prioritisation mechanisms. Or on his confident knowledge of PowerPoint's features.
It is very important is that the underlying cause and/or location is queried at each level. Do some critical analysis at each response and ensure the coachee/team is drilling downward on a realistic path. Sometimes there are multiple paths to drill, spend the time and drill them all, especially until everyone is much more familiar with the tool, at which point you'll notice far fewer possible paths to drill down as people are better expressing the correct underlying cause and/or layer first-time.
The final Why often highlights a human problem. Typically a system improvement is the correct solution to ensure the human problem is not repeated. For individual engagements this is usually a training item and/or a couple of roleplay scenarios. For team engagements it could be training or a new procedure or an update to an existing procedure. Be on the safe side and read Four Days With Dr Deming - better yet get your coachee or team members to study it BEFORE they try to fix the wrong problem with the wrong approach (and accidentally make things worse).
Done correctly, it is possible to produce a correction action or step at every level uncovered/traced that would ensure that not only the level's specific fault in this instance is not repeated again, but also to prevent similar class faults - which is a major win!