Hard drive encrypted using FileVault? Lost your password?
You can’t get your data back, but you can make the MacBook usable again:
- Start the MacBook in Target Disk Mode by holding down ‘t’
- Connect the MacBook to another computer using a Thunderbolt Cable.
- You will be prompted for the drive’s password. Click Cancel.
- Wipe the partition table of the drive using sudo dd if=/dev/zero of=/dev/diskN bs=1024k count=1 (where N is the drive number)
- Eject the drive.
- Reboot the MacBook while holding down Cmd-R to enter recovery mode. It will switch to “Internet Recovery Mode” and begin the restore process.