Below are some potential failure points, and ways to test them, in typical order of ease:

  1. Any common USB components between the CFA and disks
    • Try a different USB cable; try with or without a HUB; try a powered or non-powered HUB; try a different USB disk entirely
  2. The disk and enclosure models, if they are the same
    • You can try a different model enclosure and/or disk to isolate a problem model
  3. USB hardware of the CFA
    • Try a different USB port, including the front and back of the CFA
    • Try using the disks with another host
      1. This will likely involve formatting them since the CFA uses a Linux filesystem for archiving.
      2. Copy large amounts of data to the disks and watch for failures
      3. Reconnect and perform the tests