Overbridge don't Load + drive samples

Hi Guys!

have this problem, Overbridge don’t Load + drive samples on my imac while when i connect it to the laptop it works fine!

i have tryed to connect it directly in the usb behind the imac and also in a powered usb 3.0 hub but nothing to do!!

anyone have the same problem? how i could fix it?

then i have another questions / problem

in Synth mode when i put a cowbell or something else in chromatic mode and play it, also a kick drum play togheter with him then after recorded it sounds good, how can remove this kickdrum from it? isn’t a loaded samples because it sounds with every sound that i put in chromatic mode

thx for your help!