Audio loss in Max 5

Hi everybody, I'm quite new to Max and have been trying to set up a first audio patch, a very simple oscillator connected to a dac, and have been running into the strangest problem. When I start the dac, the signal plays fine, but whenever I stop it and try to start it again nothing happens. There's then nothing I can do to have the signal playing anymore, the only way to get it back is to quit, trash the preferences and restart, but then the same thing happens whenever I stop it. It's giving me quite a headache, and I've tried fiddling with every audio setting I could possibly think of but to no avail.

I'm on a rMBP 2012 i7 with OS X 10.8.2 running Max 5.1.3, using only the onboard sound card (I thought the problem came from my external sound card but even after unplugging I still have the problem), and here's the simple patch I have been using :

I included three screenshots, the patch, the adac settings and the same patch with a level meter measuring the signal as I first hit start proving there was indeed a signal at first.

I hope someone can help me, because I'm trying to learn how to use Max and I'm stuck on the first and simplest level, and it is utterly frustrating !
Thanks in advance !