Certain USB drives are actually a "sled" or "drive enclosure" type of USB Drive.  The Axcient-provided USB drive is this type.

Depending on the motherboard's USB chip set, Linux will see the drive as a USB, but x360Recover will see it as a real drive in an external enclosure. x360Recover is coded to only create a seed on a standard USB drive so there are times you will need to run the following command to "fake out" x360Recover, in order to see the drive as a USB for use in seed creation.

SSH into the appliance as root, with the USB disconnected, and enter the following command (all one line):

echo ENV{ID_USB_DRIVER}==\"usb-storage\",ENV{UDISKS_SYSTEM_INTERNAL}=\"0\" > /etc/udev/rules.d/99-usb-not-internal.rules

Now connect the USB and start the seed.

If you have any issues please open a ticket and we will be happy to help.