If you look in the courierd-file, you'll see this, which is what you are looking for (I think):

##NAME: ARCHIVEDIR:0 # # This is the big-brother option that saves a copy of EACH and EVERY # message passing through the system. Uncomment ARCHIVEDIR, and after # a message is delivered, its queue and data file is moved to ARCHIVEDIR # instead of being deleted. You must create the ARCHIVEDIR directory # yourself, and it must be owned by the "courier" userid. # # Also, ARCHIVEDIR *MUST* be on the same partition/volume as Courier's # mail queue directory. # # All messages will be saved into a flat directory, with one subdirectory # created each calendar day. Therefore, you will need to make sure that # your filesystem can handle it. Each message consists of two files, # the control file, and the message data file. The Linux ext2 filesystem, # for example, will start to have problems once there are more than # 32,000 files in the same directory, so if your system carries a higher # daily volume, you'll need to purge out the archive subdirectory several # times a day. # # If you fill up an archive directory, mail will continue to move, but # not archived. Caveat emptor. # # ARCHIVEDIR="/usr/lib/courier/bigbrother"

But I'n not sure if it is availeble in your version. Don't forget to check you man-pages and config-files for these issue's! Searching there will usually get you your anwers much quicker. Also, don't forget to update now and then, since updating usually resolves more issue's than it creates (though exceptions occure :-( )...

Kind Regards, Sander Holthaus.

PS: A point in general, which is slightly off-topic. I've been receiving many virus-mails (all intercepted, but that's beside the point) and some of them seem to be originating from users on this mailling list. If you are a windows-user, PLEASE make sure Windows, Office and Internet Explorer are up to date, configure them properly and also make sure your Virusscanner and Firewall are operational and fully updated!