I've recently gotten an offer to join McKinsey as a business analyst. I received the interview invite 10 days before the first interview and had never done any consulting case prep before (Case or PEI). I was also working full-time during this time.
I posted a post here titled "Guidance for prep for McKinsey interview in 1 week" on October 17th and received a lot of disheartening comments from coaches. Most said it would not be possible and some were downright rude about it. Many of those same coaches then messaged me saying it could be done with their help... I wanted to make this post to tell anyone in a similar situation that you can do it!!
Now I will note that this is not optimal and the earlier you start the better. This does not mean that all hope is lost. I didn't end up getting a coach and managed to do 10 practice live cases before the first interview. Happy to share my process with anyone in a similar situation!