Nasty, foul mildew odor from vents

I've got a 2004 CR-V that has the foulest odor coming from the vents. It smells like some kind of mold or mildew. It's not constant though, really just when you first start the car up and last for a few minutes. I've replaced the cabin filters and they were fine. Didn't smell at all. I can't figure for the life of me where the smell is coming from though.

HELP!!!

Blast out the intake vents below the windshield on the outside with compressed air.

Do that, or if it really bothers you that much, pull the vents out and visually inspect them, but thats a lot of work

clean the condensor its by the blower box and ur runoff hose is probably plugged u know how u see cars have that little puddle of water after they leave thats condensation buildup and some of it stays in the condenser and hence the foul odor they sell sprays for it to do the job the proper way not half fast