the iPhone SDK 4 requires at least 10.6.3 i have a problem i have installed mac osx 10.6.3 iAtkos s3 v2 on my Dell studio 1537 and all drivers works except the USB i have installed the iphone sdk 4.1 and i have installed it and it works fine, but after i restart my laptop and try to enter the mac again it gives me an error msg "Please, hold down the power button and try to restart your machine ..." i tried to only install mac and other programs and it works fine only when i install the ios sdk 4.1 it fails !!! any solutions ??? Thanks a lot, Saad !