I cannot seem to win with this never ending SDK upgrade fail problem. At least people have the option of keeping around a .bin file from an older SDK installation and use it on the current cgminer provided the kernel hasn't changed in the interim. No solution seems optimal, and most of the problem seems to surround the optimisation cgminer does by caching the .bin file which speeds startup of cgminer significantly. If I forced it to build the kernel every single startup, there would never be this confusion, but startup would be butt slow if you had lots of GPUs whereas now it starts hashing in the blink of an eye after the very first startup.