So I decided I needed windows in order to run some programs in my Imac late 2011. Then problems started: 1- OS didn't offer me the option of booting from a USB -- Solved 2- When created the boot USB, the computer didn't recognize a bootbale USB when restarting --- I solved it too 3- When the Boot USB was detected and started installing windows an error message came up when I chose the bootcamp partition, saying that is was MBR and windows can only install on GPT.--- And here everything went wrong. I saw a video on youtube showing a way to install windows, by cpressing shift+f10 then run diskpart on the console (all this in the windows installer) and then chose the disk and have it changed from MBR to GPT, and so I did. Everything worked flawlessly, but apparently the change from MBR to GPT was not only on the partion but the entire HDD, and OSX has disappeared. I've tried booting pressing option, but only the windows EFI partion appears. If tried booting internet retore and nothing happens, and I don't know what else to do. I really need help. Has anyone gone through the same or knows how to solve it? Preferably without wiping my OSX files. Thanks a lot.