I did the same thing as mentioned by the poster of this question and I am facing the same problem. My Mac is not booting in OS X and I am unable to find the startup disk also. I gave the same commands and found that the partition type is changed as OP's.

  • @klanomath I did not try your answer as I don't see partition 3 and 4 as other have. I have only 0,1,2 and partition 2 is my main which has data(Which has partition type as FFFF…). I wanted to be sure before trying out anything.
    – akm
    Commented Nov 27, 2017 at 14:44
  • @akm You should add some details like the HD type of disk0 (e.g. SSD), the installed system on disk0s2 (and disk1s2 which seems to be a second working boot drive), whether disk0s2 was encrypted etc. If you need further (personal) assistance you'd have to download & install TeamViewer and send me an email with your TeamViewer credentials
    – klanomath
    Commented Nov 27, 2017 at 14:49
  • @klanomath 1) disk0 is my internal drive which is SSD. 2) I pressed alt/option button while reboot which displayed 4 options(backup from time machine, get online help, reinstall os x, disk utility). Here I chose to reinstall os x by inserting a external hard disk(which is HDD) and i installed it on the external hard disk(since internal SSD was not showing here). Now, after inserting the external hard drive, if I reboot my system, it is automatically booting from external drive(which is OS X Lion). 3) I think, disk0s2 is not encrypted.
    – akm
    Commented Nov 27, 2017 at 15:03
  • @akm You still didn't mention the original but "vanished" system on disk0s2! Did you upgrade it to High Sierra previously? I recommend to upgrade your "temporary recovery system" on disk1s2 from Lion to Mavericks or much better: High Sierra - if possible. After upgrading Lion to High Sierra we will attack the main problem.
    – klanomath
    Commented Nov 27, 2017 at 15:09
  • Original is sierra. I am upgrading to El Captain in external HDD then will update to High Seirra as we can't directly goto High sierra from 10.7.5 Lion :)
    – akm
    Commented Nov 27, 2017 at 15:25


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