Don't expect me to write what I wrote on a forum two years ago ;-) You probably have some DSP object which is doing something not really good… The best thing would be to remove DSP objects "one by one" until you find the culprit. Are you using some third party externals?
FFTease (codepend~ only) [I suspect this is the culprit]
It doesn't happen all the time, in fact, it happens only rarely. So that makes it harder to delete the one object and just wait. Is this something to be expected from an older external (like Max6 compatibility type stuff)?
Just to go on with the toppic, and hopefully to fin a solution for this "problem". I am just doing some multichannel tests and try to reproduce some crashes of Max 6.1.3. I use only the Audio Tester, no other patch is open. The tester sends oscillator pulses every 250ms while stepping through 32 output channels. I always get these "freeing zero signal?" messages. Not a lot. Maybe 1 every 15 min. I also changed the Audiointerface: 1st I used a USB Madi Device, 2nd I used Jack Audio Connection Kit. Same problems with both devices.Then Max crashed after an hour the last four times. ...
In the morning I programmed in MAx (without the audio tester) - I havn't had crashes.
MY Machine is a Macbook Pro 13" from Mid 2012. OSX is 10.8.4. Nothing else to say at the moment ;)