A typo in your command, however missing `-A' or `--aiff' or `--format=aiff'.
It works

csound -A -o test.aif test_8ch.csd

file $SFDIR/test.aif
test.aif: IFF data, AIFF audio

sndfile-info $SFDIR/test.aif|grep ^Channels
Channels    : 8

tito

On Sat, Jul 21, 2012 at 12:29:19AM +0100, peiman khosravi wrote:
> Today I noticed that when I render an 8-channel csd to aif file (csound -d
> test.aif -d) maxmsp seems to register it as a stereo file. I re-saved the
> file in a wave-editor and it worked fine. Is it a header issue?
> 
> Thanks
> Peiman