I have had Advanced Task Killer on my phone from the day I got it back in early November. I did not experience the loss of email settings or my SMS threads until the update that I received on 12/11/2009Whoever mentioned the Advanced Task Killer, kudos to you on that -- all three of the phones I am seeing this issue on have that installed. So does mine of course, and I haven't lost my e-mail account. I wonder if that could be the cause of this problem! I have some exclusions set in ATK, including the messaging, email, gmail and a few other apps. I do use the "Press to End" widget that kills all the apps quite often but I have never had this issue like my other users have. We all have Droids. Some have had the problem on 2.0, and now all of them have experienced it again on 2.1. One guy has had this happen to him 3 times now, the others all twice.