Problem happening after installing Thunderbolt Software Update 1.2

Hello experts! I have just installed the thunderbolt software update 1.2 into my Mac system and I do not know why but my Mac is really causing a lot of troubles! It is not opening up – gets stuck in the boot screen. Why has this happened? Can anyone tell me how to fix it with possible solutions to possible reasons that might have caused the problem? Please help as soon as possible.
