I'm running 10.3.5 and very werid things are happening. After going to sleep by itself- most of the time when we wake it up we only get a black screen with a cursor- have to restart the computer. I have a username that I don't use very often and I had filevault on and reset Safari one time before logging out which I have done before many times. The next time I logged into that username all my preferences had vanished including my add on mouse prefs, expose, etc. IN addition, all my documents, pics, etc were moved and there was a file with my username.sparseimage there that has a filevault icon on it. I double clicked that and it mounted that white icon/drive looking thing and I was able to find my files inside that folder to copy to the regular documents, pictures, etc. folders in that same username like I had them before.