Assuming a PL-2032, Have you tried the alternate open-source drivers? http://nozap.me/driver/osxpl2303/index.html http://nozap.me/driver/osxpl2303/index.html T

Assuming a PL-2032, Have you tried the alternate open-source drivers? http://nozap.me/driver/osxpl2303/index.html http://nozap.me/driver/osxpl2303/index.html That fixed the KP for me and got break to work which didn't out of the box. Before the updated drivers I worked around the KP by closing cu/screen before unplugging the cable.