When ever I shut down my Mac computer resets all my preferences to Safari and Mail. I do not want to use either of these programs - I use Firefox and Thunderbird. It is really annoying to have to set my preferences over and over and over again. I have set them through both the software preferences location as well as the System Preferences locations. It makes no difference to do one or the other or both this continues to happen. I realize this is more likely a Mac problem but hoping someone here has come across this and figured how to deal with it! Thank you.