Hi, i having saming issue, but quitly different. In My case, my keylab essential 61 , is installed on Windows as a keylab essential 49, some keys (C3, D3, e last octave) didn´t work, and some keys taking different notes, but in some cases Windows detect the correct driver (Key lab essential 61), in this case, everything works fine. I believe that´s is not a hardware problem. Tried in diferents computer, and same behavior...