I followed all the instruction for bootcamp and did everything how it was supposed to be done. But once the mac restarted it shows a black screen with a text saying "No bootable device - please insert device and press any key". I do not know what the problem is here but if someone could figure out how to fix this it would really help. Im running on a Mac (27-inch, Mid 2011) OS X El Capitan. I am also trying to bootcamp windows 8