There are no 6TB or up 2.5" drives. You will need to go external. And you want CMR drive, not SMR. The largest CMR 2.5" drive ever was 3TB and is no longer made. Largest current model CMR 2.5" drive is 1TB. For external the enclosure would/will be very important, many/most will not work. Check the community for models that will work, in fact it is better to go direct Sata to Sata on the drive that will be inside the enclosure, rather than Sata to an Esata port on the enclosure. If you buy a correct drive (ie not SMR) the Edge should format it itself.I want to buy my third Tivo, the Tivo Edge Cable 2 TB but before using, want to install a bigger hard drive. I watched the Weaknees upgrade video. Which brand is best and what size? Are there any available hard drives that are 6 TB or bigger that can fit in the same Tivo hard drive tray? Trying to avoid external hard drive case. Also, is there a way to avoid having to format new hard drive before Tivo formats? Thank you for your help.