I ran into this issue in March 2012 while swapping the factory drive of my 2010 Mini with a larger and faster 7200 RPM drive... Ended up leaving the screw out... Tried again while upgrading to an SSD late last year... Got ambitious this afternoon and found this post with a Google search. Following x10target's hints, I managed to align this properly and replace the screw for the first time in nearly two years. Hooray! That is one tricky little bastard, indeed!