I have a late model imac 27 with osx mountain lion. I am trying to install ubuntu using virtual box. I have ubuntu 12/64bit on a mac formatted flash drive and on a dvd. The computer doesn't recognize either one of them. States: Fatal error - no bootable disc Any suggestions?
try to download the ISO of Ubuntu not via HTTP but by using a bittorrent client like transmission and, when the download has finished, burn this ISO. At least as I have experienced, Bittorrent is a safer way for downloading the ISOs of Ubuntu.