I created a bootable usb with ubuntu , choosed to erase mac osx and use the entire hd just for ubuntu . The installation runned well but going to the first reboot , the mac doesent startup linux . I had earlier windows in another partition than os x and I could choose betwwen them but Now it appears only "windows " but actually it is deleted and if runned it retuns "missing operation system" . Is there any solutions ? if I make a bootable usb with windows there is going to happen the same ?