It's not possible for Outlook to download mail while it is closed. It it
appears to have happened, then Outlook must have been running even though
you thought it was closed. "

Nonetheless, that seems to be the case! I have none of the programs
listed on the link you gave, but one of them led me to a utility which
can verify if Word or Outllook is running in the background, so I
installed it, and it wasn't...

Liz