We seem to be finding some USB hdds (and USB pen-drives/thumb-drivers) work fine as dynamic units, while others do not and display as "not compatabile".

Open-E support feel that all USB hdds should be supported, but there is no formal testing process of all avalable devices (reasonable!). So we're after user experiences.

Successful…
- Seagate (genuine) 500GB external Hdd
- A no-brand USB external enclosure with Seagate 80GB SATA Hdd fitted

“Not Supported”
- Seagate Momentus 100GB ST9100828 USB drive
- Corsair 4GB USB pen-drive
- 8GB Kingston DataTraveler 2.0

Hardware is Intel SSR212MC2. In the Bios (Advanced/USB Configuration), there’s a list of USB devices detected, and has the ability to manually specify the USB type, so we tried setting the USB pen-drive to “Hdd” (by default is “Auto”) in case the auto detect was wrong, but still the message was “unsupported”. All these devices do work correctly on other systems.

This post suggests it may be the presence of an existing partition, but the devices that did work for us had partitions on them, so this is unlikely.
Thanks