Hello, I have 2 External USB Maxtor (now Seagate) Hard Drives. Both are USB, and do not require additional power. At this point in time, Windows Vista does not seem to want to allow me to view and access both drives at once. Only one drive displays in My Computer. Both drives show in device manager, and show as working. In the disk management console, they both show as present, however one drive refuses to initialize or accept a new, simple volume. Any ideas?
Are you connecting them directly to two ports on the computer itself, or through a USB hub? If it's through a hub, especially an unpowered hub, that will be the problem. Disks draw quite a lot of power and only a directly powered port will be able to provide enough juice to run it.