Ok, as you know, I expanded my Premiere 4 to 2tb, works good! I said I would get an expander. WD, certified for tivo. I plugged it in, it went throught its 'adding space' messages, and rebooted. Upon reboot, it went into the expand space message again So the conclusion is that you CANNOT add an expander to a JMFS 1.04 upgraded internal disk. I'm sure it is a partition thing. My thoughts... I think an 'Apple_free' partition (as partition 15) needs to be made to force a partition 16/17 pair as free. Which Tivo must use to add an expander. I think JMFS needs to figure out how to add a coalesced partition. IE, add the new expanded space into the other MFS region on the disk. Not adding a new MFS region. This might require using JMFS on a no-data disk.