Reply #3: Well, that's not good. If it recognizes thumb drives but not the external, something is screwed up.

[HopeHoops]

One other thing to try, odd as it may sound, is a different USB cable. The contacts actually do suffer wear and eventually become less reliable. The ports on the laptop may be more worn than those on the desktop so it might not be getting a clean connection. It is a long-shot, but worth a try.

On another note, I've had various drives that wouldn't work on some machines while working fine on others. The only kind I've had pretty much 100% success with is Seagate. I've got 6 TB of external drives hanging off of my desktop full-time, through hubs, and another 4TB or so of externals I use for the laptop on an as-needed basis - all Seagate. I've never had a problem with any of them.