To be hired Microsoft has two stages.
Initially you will be provided with a phone interview (30 mins) or On-Campus interview. You may be asked a technical question. Be prepared to answer questions related to your background/projects.
I passed this stage and in about a week I was notified that I will be moving on to their on-site interview in Redmond. I was given about a months time between the phone interview and my on-site.
Depending on your process, you will either be going to Microsoft Building 111's recruitment event where you are cycled through 4 interviewers between you and 10 - 20 other candidates, or meeting with a recruiter and then going to another building to interview where you will have 3 - 5 interviews, including a lunch interview.
This time I was selected to interview with 3 - 5 people in the Office team. You are not given your team beforehand. The team you are interviewing with may also not be the team you end up working with.
The problems are algorithmic in nature and you are expected to test and clarify requirements. Each interview is about an hour long and between each interview you will be taking a break while the interviews discuss among each other about how you did.
From what I have understood each interviewer has a hire/no hire decision. If you receive 2 no hires out of your first 3 interviews, your day may be cut short. When you reach the 5th interview, (s)he is the hiring manager and ultimately has veto power.
For me it was a rather discouraging experience. I made it to the 5th interview. I felt I performed very well, giving them optimal solutions, and struggling with only 1 and a half of the 6 problems I was asked, but ended up solving them optimally in the end. However, I received the discouraging call later that week that I would not be hired. It didn't make sense to me and I tried to reflect on how I could have done poorly being very familiar with technical interviews at this stage. I felt that what I had to nitpick with myself what I performed weakly on. The most discouraging part is how they will not tell you anything aside from apply back next year. At this stage I'm not even sure how to improve since I do not think I am technically lacking and I did not believe I came off rude or obnoxious during the interview. Just my luck.