I cannot imagine why your Preferences are not "sticking." Can you furnish the full specs. of your computer (especially Audio sub-system), your version of PrPro, etc.? For more info on what would be useful, please see this FAQ Entry: http://forums.adobe.com/thread/961741?tstart=0
Here is what I have:
I am using PPro CS6. I have a Alesis 2 channel soundcard/mixer and two Samson Resolve A6 studio monitors. I am on an iMac. Here is what my iMac sound settings are set to:
At least once a day while editing PPro pops to this setting and the only way I can get audio is to click it back to "System default settings". It does this all the time.
I hope this helps.
Thank you for that info.
As I am a PC-only guy, I am going to step away, as I would most likely provide you with useless info, or perhaps totally incorrect info. I am sure that a Mac-user will be by with helpful input. They should be able to use that info.