Hi, have you checked on System Information to make sure the Mac is actually recognizing the hardware? (type system information on spotlight and click USB on the left)
I had a simmilar problem with a Seagate Freeagent Go drive. It showed up on the hardware list for a few secconds and then dissapeared as if I had unplugged it, meanwhile the HDD was still on and spinning. Called Seagate and they told me to do a PRAM & SMC reset, this solved the problem, although it still happens every now and then.
Mac OS X can see NTFS formatted drives too, the only limitation is that it can not write on them (without third party add ons) so I doubt it's a formatting problem.
I'm not sure if you are having the same problem, but you should give it a shot.
SMC Reset
For Portable computers that have a battery you should not remove on your own
- Shut down the computer.
- Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
- On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
- Release all the keys and the power button at the same time.
- Press the power button to turn on the computer.
Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.
PRAM Reset
- Shut down the computer.
- Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
- Turn on the computer.
- Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
- Hold the keys down until the computer restarts and you hear the startup sound for the second time.
- Release the keys.
Your computer's PRAM and the NVRAM are reset to the default values. The clock settings may be reset to a default date on some models.
Let me know how it goes.
ps: sorry for my english, it's not my native language!
