Had a strange issue with my Mac where the password box was not popping up and I couldn't log-in. I think it is 2014 model btw. So I tried to delete the HD and reinstall. I think I also have restored the 1.51 Gb OSX base system back on and it no longer appears as an external disk. It also does not let me delete the HD in disk utility now and only gives me the first aid option not grayed out which quickly reports no issues. Real Problem: When trying to reinstall the HD is grayed out and it says "this HD is locked" preventing me from reinstalling. I found some posts and tried to apply what I read; when I use the terminal and command: diskutil cs list It replies with : no CoreStorage Logical groups found When I use command: diskutil list Reply is: /dev/disk0 (internal, physics): #: Type Name Size Identifier 0: GUID_partition 251.0Gb disk0 1: EFI EFI 209.7Mb disk0s1 2: Apple_HFS OS X Base System 250.1Gb disk0s2 /dev/disk1 (disk image): #: Type Name Size Identifier 1: untitled. +5.2Mb Disk1 It goes on for another 15 disk to 16 all maker identical to disk1. Also I cannot boot the Mac; it goes straight to recovery options and if I try starting it with r+CDM held it actually does nothing it seems. Any help would be very very greatly appreciated please.