I am using a SEAGATE - FreeAgent Desk HDD 500 Gb/Go USB 2.0,
I know it is not on your list of drives that have been tested,
but its one I own so I thought I would try it.
It worked fine for about 5 minutes and would then hang and not work again until the Qu was rebooted.
The problem is caused by the sleep interval time settings on the HDD,
Resetting the sleep interval to NEVER, is discussed on Seagates forum <here>
Seagate Engineers did NOT put a sleep interval time adjustment in the OS X version
of the Freeagent drive manager utilites program, but they did put it in the PC version.
Seagate Tech Support told me that I would have to reformat the disk for the PC,
install the Freeagent drive manager software on a PC,
Set the sleep interval to a longer time or to NEVER,
Now reformat again to OS X.
This should fix the problem."
The FreeAgent drive utility needed to reset the sleep interval from a PC should be available from the Seagate website.
Please contact Seagates Technical Support directly for further assistance.
Related article: Qu-Drive. Understanding Qu-Drive and USB <here>
containing a list of A&H tested and approved HDDs
keywords: Qu-16 Qu-24 Qu-Drive Qu16 Qu24 Q16 Q24 Qu-32 QuDrive HDD Seagate