It really tough time when Mac OS X 10.6 blue screen at start up appears. This type of problem rarely come across in OS X 10.6. But when it comes your system would gone unresponsive and does not start. Take an instance wherein as usual you try to start your Mac Snow Leopard(OS 10.6) but it failed to start. And a the same time unexpected blue screen along with pinwheel would be seen and your system unlikely turned into a scary note. Since the Mac does not boot that's why there is no further data accessing take place. Well this mac os x 10.6 blue screen at start up incident could happen with any one of you. It has been found that this problem may arise due to incompatible startup items or damaged applications. So in order to overcome from this trouble one can try starting Mac in safe mode. If it works then restart the system by selecting Apple menu. In case it failed, repairing startup disk permission through disk utility is another option to resolve mac os x 10.6 blue screen at start up issue. Ultimately if all these measures failed installing OS X 10.6 from installation disc and recover lost data from backup. In non availability of backup opt Mac Data Recovery Software.