Hi All, I bought a 500GB Hitachi 5K500.B to replace the 120GB Toshiba drive in my 2006 1st Gen Macbook and for some reason it doesn't fit. This drive is listed as compatible and is 9.5mm in height (confirmed on the Hitachi site and also putting the 2 drives side by side) so it should fit. When I attempt to slide the drive into the bay there is something preventing it for going in fully. I can't determine what. All the search results via Google say this drive is fine to use. Any ideas? Thanks!