[hi] menu elements missing in OSX 10.6.8

Hello,
In performances I heavily rely on a patch that uses the computer keyboard as a HIDevice and translates its input into MIDI messages. On my system the device that gives access to the keyboard is "Apple Internal Keyboard / Trackpad 4"
Sometimes my patch doesn't work and I have found the reason to be that in those cases the entry "Apple Internal Keyboard / Trackpad 4" is simply missing from the [hi] related menu list.
I realize this is probably not max-related, rather something that has to do with the OSX system configuration. When it happens, it will affect any version of Max Runtime I have on my machine and also my M4L patches. And then, the problem would go away from itself. I cannot reproduce the problem on purpose, nor do I see a system to fix it. I do the usual things, reboot, etc... Eventually I get my Trackpad 4 back, but last time it took an hour, which can be extremely annoying before a performance.

There is hardly any information about the OSX specific HI devices out there so I thought I would ask here. Maybe someone has come across something similar.
Thank you for any hint,
carloskleiber