So I am trying to install Windows with Bootcamp. I am running an early 2011 17" MacBook Pro on El Capitan. I go through the process in Bootcamp and reboot into EFI and here lies the problem. I follow process through to format and then it will not install to drive because it needs to be GPT rather than MBR. I have found threads with this issue here: http://macriot.com/mcrt/?p=2362 I have followed the thread in what to do and written sudo gdisk/dev/disk0 and given password but I get command not found. Any ideas how I can get round this please? I have tried this for days now and have to keep restoring OSX from a backup to give it another try.