Microsoft·Software Engineer·Technical Phone Screen
Apr 2026
Microsoft phone screen for a software engineer role, split into a resume walkthrough and then a pretty brutal concurrency coding section. The second half was no IDE, just you and a text editor explaining deadlocks in real time. Not a relaxed conversation.
- Walk me through your resume and a recent project, including the trade-offs you made and what specifically you contributed.
- Here's a classic dining philosophers setup. Write the code, explain exactly why it deadlocks, and then refactor it to be deadlock-free.
- Two threads acquire two mutexes in opposite orders. Explain the deadlock and show how to fix it using consistent lock ordering.
- In a producer-consumer scenario with a bounded queue, what goes wrong if you hold a lock across a blocking call, and how do you fix it?
- How would you detect a deadlock at runtime in a production system?
“Thought this would be the easy warmup.” The rest of the author's notes on Software Engineer interview at Microsoft, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.
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