Please help with this, I don't know how I managed to mess this up. What can I do to fix? Was doing a clean install wand wanted to erase the disc. --- Post Merged, Apr 18, 2016 --- In meantime I have plugged in a blank external drive and installed OSX on that. Do you think after that if I do a clean install a master boot record will show up? Have I 'bricked' my MacBook?