INDD CS6 reverting to default prefernces

Indesign CS6 keeps randomly converting the preferences back to default settings. Have, on quite a few occassions now, converted the preferences. I have uninstalled and reinstalled INDD but it continues to revert back. Can anyone offer a solution or reason why this might be happening. Thanks! Oh and yes, there has never been documents open whilst changing the preferences. It will work for a few days, then randomly it changes back to default.