I often wonder whether in-situ O/S "upgrades" should be banned/outlawed/eliminated. Imagine that you could only be install a new O/S to a nice clean formatted partition. That way youl'd never worry about data loss (what do you mean you have your O/S and data on the same partition!?!?) Further, each O/S should provide a utility whereby all preferences, settings, wallpapaers and associated auxilliary data can be backed up with ONE KEYPRESS, and then reinstalled on top of the new O/S, once that is in place. Can you IMAGINE the hours and anxiety saved?... Oh well, we can all dream...