Smell like "blue cheese", why and how?

[peterjaw]

Hi guys,
My E70 was delivered on September and totally 5000 km (3100mile). I only park my lovely E70 in parking deck.

I found that whenever I turn on the A/C, there comes very disgusting smell, like blue cheese. But after 1 or 2 minutes, the smell gone. This happens only when I turn on the compressor, if I turn on the fan only, then no such a phenomenon.

I know that when something contaminate the pipe, this could happen. I have checked over and found nothing. Beside, my car is quite new, and
I only park my car indoor.

Does anyone have similar or same experience?