Thanks to Presonus support, I was able to solve the problem of the "PreSonus FP8" midi port not found by Windows 10 (64b). This problem occurred immediately after updating the firmware from version 1.00 to 3.32. I solved using another computer (with the same operating system) to perform the firmware update. Now Studio One 4.5.5 works perfectly with Faderport 8. However I would recommend the Presonus developers to provide a dedicated driver. Giancarlo