Strange. I have several USB 1TB drives plugged in, and works like a charm. I remember reading the N2200 supported up to 4TB drives internally, it should be the same externally. Perhaps try the new firmware and see if that helps. Have you tried your 2TB drive in another PC? What brand is the HDD/External Case? What file system were you using on the HDD? It is an old post anyway, I just felt for you if you hit a dead end.
A USB flash drive is a data storage device that includes flash memory with an integrated Universal Serial Bus (USB) interface. USB flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g. As of January 2012, drives up to 512GB were available, with 1terabyte (TB) drives in planning. Storage capacities as large as 2 terabytes are planned, with steady improvements in size and price per capacity expected. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and a 10 year shelf storage time.A USB drive -- also known as a flash drive or keychain drive -- is a plug-and-play portable storage device that uses flash memory and is lightweight enough to attach to a key chain. A USB drive can be used in place of a floppy disk, Zip drive disk, or CD. When the user plugs the device into the USB port, the computer's operating system recognizes the device as a removable drive and assigns it a drive letter.