With Apple releasing its next gen OS Mountain Lion, jailbreak users who updated to the said OS experienced problems while using their trusted jailbreak utility RedSnow for jailbreaking their iOS devices.
Fortunately there is no need to worry since the Dev Team not only confirmed their existing jailbreak utility to be compatible with the new OS, they also sent out some instructions to guide the way.
So if you have installed Mountain Lion, and you plan on using the utility, following is what you need to do :-
Update #1 7/25/12: redsn0w is compatible with retail release of Mountain Lion OS X 10.8. Until we start using an official developer ID for it (!), you’ll need to use the new Ctrl-Click-Open security bypass the first time you run it after downloading.
Other than that, you shouldn’t have any problems with RedSn0w in OS X 10.8. For the latest stable release of RedSnow, headover to this LINK to download 0.9.14b2 version of this jailbreak utility