audio issues with Max 5

When I open Max and create a simple [cycle~ 500] into a [dac~] I do not get any sound. I figured out that if I deleted my audio preferences in the Max Preferences folder, booted Max and turned the audio on, and then built the same patch, I could get a sound. I then did the whole deletion and rebooting process again, but this time I opened up a previously made patch. I could get audio; however, once I began modifying the patch, the audio went out and wouldn't come back.

Is this a vector issue or does anybody know what a solution may be?

I use Mac OS X 10.6.8 and Max 5