Talked to everyone.

Are you guys sure shopping and wandering around will trigger it?

I read somewhere that only a mission can trigger it...

I always thought they were triggered by talking to the yeoman chick. Just keep asking her about the crew. After you successfully recruit Tali, she will get a message from the migrant fleet and will want to talk to you about it.

have you done all the side-missions? including the ones you can just stumble upon?

Post limit.