I was in the process of doing a long sync to my iRiver and accidentially pressed the CLOSE WINDOW X in the top right hand corner of MM.
MM rightly objected with a message...
There are background prcoesses running. Terminate them?
with two buttons YES and CANCEL
It took me 20 seconds to work out which one I should press.

Dose CANCEL mean cancel the processes? Nuh.. try that... phew...