For Sandy Bridge users updating to OS X 10.6.8 ONLY. Run this tool before running the 10.6.8 Combo Update. More details on the blog here:
https://tonymacx86.blogspot.com/2011/07/get-ready-for-os-x-lion-update-to-1068.html
https://tonymacx86.blogspot.com/2011/07/get-ready-for-os-x-lion-update-to-1068.html