Unfortunately, this controller is not for me to use: In the middle of actions (eg backup) "disappear" the controller and thus the connected drives and are untraceable / visible (driver issue?). Only after restart everything again - seemingly - neatly displayed. But then the same effect repeatedly crash, attached drives no longer recognizable. Schade and annoying. Thanks to Amazon, the reversal is however problem. It remains seated "only" to the return costs.