This issue may be seen with all FreeAgent Go drives (excluding the FreeAgent Go classic drives, which are brown in color) while connected to a Mac via USB.
The reason for this issue is because some Mac systems do not provide enough current (power) through a single, USB port to enable the FreeAgent Go to properly spin up and enumerate (be recognized/seen) on the system
Use the 1394b connector (on the supplied dock or cable) with the EDA. This will actually give the customer the best performance as well as allowing to the unit to enumerate easily.
Use both the USB power and interface cables. The user will need to plug both cables into the system first, then plug both cables (in either order) into the FreeAgent Go within 2-3 seconds.