That time when I failed the Microsoft interview | Adolfo Ochagavía

That time when I failed the Microsoft interview

28 Jul, 2026

The year was 2015, halfway through my Computer Science bachelor’s degree. I had spent a few months contributing to open source and my confidence levels were high, so I thought: why not aim for a summer internship at Microsoft?

Microsoft, of all places, might sound like a weird company to target in 2026. Back then, however, they were cool (in my book at least). I was impressed by their work on Typescript, and also by their open source rewrite of the C# compiler. I dreamed of working together with people like Anders Hejlsberg, Joe Duffy and Eric Lippert1.

Somewhat naively, I sent an email to someone listed on the Microsoft job portal. I didn’t know which internship to choose and I hoped talking to a person on their end would enlighten me. I attached my resume just in case that would be relevant.

My naiveté was rewarded when, about a month later, I received an email from a member of their university recruiting team. The subject was “You’re Invited to Microsoft Phone Interviews”. They wanted to talk to me!

What now? First thing was to book a spot. I lived in The Netherlands and was 9 hours ahead of the Microsoft people (they were on Pacific Time). There wasn’t much choice, then; it would be an evening call on my end, morning on theirs.

With scheduling out of the way, the next step was to start preparing. Internet lore unambiguously recommended “Cracking the Coding Interview”, a book where Big Tech interviewing practices of the time were unveiled to the uninitiated. Drawing from the book’s advice, I prepared answers for so-called behavioral questions, made sure my knowledge of data structures was fresh, and even went through a bunch of brain teasers.

Then came the day of the interview. I found a quiet room for the call, laid my interviewing notes next to my laptop, and joined the meeting with a mix of curiosity and nervousness. Guess what? “Cracking the Coding Interview” proved astoundingly accurate. Behavioral questions came in the expected flavors, and my notes allowed me to answer them without breaking a sweat. I even got a brain teaser straight from the book! It was something along the lines of:

You have 12 marbles and a balance scale. One of the 12 marbles is inconsistent with the others, meaning it could be heavier or lighter than its peers of normal weight. You are allowed to use the balance scale exactly 3 times to identify which of the 12 marbles is irregular AND determine whether it is heavier or lighter than normal.

(source)

Now I faced a dilemma. On one hand I could pretend I didn’t know the riddle, put on an act of thinking out loud, and let the interviewer believe I had arrived at the solution on the spot. On the other hand, I really didn’t feel like pretending! Besides, isn’t honesty more valuable than the ability to solve riddles under time pressure? If a company is unable to see that, then that’s their loss, I thought.

You can already see where this is going to end! I told the interviewer I already knew the riddle, and I asked for another one. She was a bit surprised, but after a short pause gave me the new riddle I had just asked for. This one was not in the book… this one I was unable to solve under the pressure of the interview. How uncomfortable!

Be that as it may, the interview continued until its natural end. After the call I was left wondering: will they value the boldness I displayed when it came to the brain teaser? I laughed a bit at my own idealism, made peace with either outcome, and decided to tone down my expectations just in case.

As it turns out, my toned-down expectations were duly met a month later, when I received a follow-up email:

We have carefully considered your qualifications and skills.  In light of our current opportunities, we will be pursuing other candidates whose background and abilities more closely match our needs at this time. If you have any questions, please contact your school recruiter.

Oops!

Maybe Microsoft did want interns to solve riddles as part of their job. Or maybe I screwed up something else. I’m afraid I’ll never know!

Eric had already left Microsoft, but I loved his blog and thought well of the company for having employed one of my programming heroes. ↩︎