How many TB need to be unused for a 10.9TB drive to not be in the "red zone" of your PC's Drive list? My 12TB has actually 10.9TB available for use and I have used all but 800GB of it. Is there a real reason why it goes "Red" at a certain point. My 4TB HDD seem to need approx 400GB of spave left at the end so to speak. Is this really necessary? is there a set amount that should be left per TB? Thanks for any info. Just really interested if anyone has a real answer to this because I looked online and didnt see any explanation. FYI, I usually leave about 200-250GB on each drive whether its oin the "red"zone or not. Is that bad? Cheers