I have a 17 inch Macbook Pro i7 Late 2012 and a i7 imac late 2011 and have connected them by thunderbolt cable, I have tried to make my iMac into a target display but it will not work. I have pressed cmd +F2 on either the mcp or the iMac. I know the MBP works with an external display as I have connect it to a pc monitor using mini display port. I haven't tried the iMac yet but maybe I am doing something wrong. Anybody had this problem if so what is the cure.