???? I had a new 200gb Maxtor H.D that I had formated by you guys about 4 - 6 months ago to use as a primary drive to replace the original 80 gb HD that was in my Samsung 4080 D.tv tivo, however after a few months the unit couldn't successfully make a daily phone call anymore so I just deactivated that unit and sat it on my closet shelf and I just got by with my other Samsung ( 4120 ) ,recently I decided to see if the Maxtor HD would work as a primary Drive in my 4120 since it's close to becoming full to it's max 100 hr's total availability ,after switching the drive and restarting the 4120 back up it gave a message saying that there was" a hardware problem that until it was resolved the unit wouldn't be able to either record or show recorded programs",so I went to the reset & restart unit in setup and had it restart the recorder,and when that didn't work I tried the clear & delete everything but still got the same message,so I recently purchased another 4080 off ebay and it checked out ok as far as I could check it out without actually activating it, so I decided to do the same swap with it and got the same message and the same results as with the 4120 after trying the same troubleshooting steps,so now I'm wondering if the h.d has to be matched up with the units ID # to work in that unit,as I thought that as long as the replacement HD was formated as a primary drive for a Samsung it would work in any Samsung,so is my assumption wrong ? as soon as both drives were placed back in the units they were originally in they both worked ok,sorry for the long post but it was necessary,and thanks in advance for any help .