After deleting Win at partition 3, there is still Windows option at startup

Discussion in 'Windows, Linux & Others on the Mac' started by actasci, Dec 18, 2013.

  1. actasci macrumors newbie

    Mar 27, 2011
    I bought an SSD, and hooked it with my old hdd to my system. There was a Mac and Win partition in my older drive. I erased system files, but couldn't formatted it because it has important info.

    Now at startup (the screen comes after pressing alt button at startup), i managed to erase second Mac option and second Recovery option, but there is still a second Windows option, which linked to nothing.

    My question is, how can i delete that obsolete option at startup? Is there anyway i can manually arrange that screen?
  2. murphychris macrumors 6502a

    Mar 19, 2012
    The Boot Camp documentation says Windows can only be removed with Boot Camp Assistant, which would have removed this Windows boot option also.

    Alternatively, there are commands in Terminal which can remove it. First use the command 'diskutil list' to find the number of the older disk, it's probably /dev/disk1 but you should make sure.

    The next command is dangerous if it's mistyped.

    sudo dd if=/dev/zero of=/dev/diskX bs=440 count=1
    That writes one count of 440 bytes of zeros to diskX. You need to replace X with the number of the drive that had Windows. This removes the Windows bootloader, and the Apple firmware will no longer produce a Windows icon if this bootloader code is missing.

    It should be obvious, but if you forget to include count=1 this command will write zeros across that entire drive and there will be no recovery possible.

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