http://forums.steampowered.com/forums/showthread.php?t=1156864

No I don't know what's causing it or how to fix it. However just know that you/I are not alone and a fix will probably come eventually.


I am one of the people affected by this and given that a large portion of my list was in this Steam group, if anyone needs to contact me (or you also are missing your list and need to contact others), you are free to use the Group Chat feature for this Steam group; just click the "_ in Group Chat" button next to the group title.