Getting fsck not done error during boot During starting up, I always get "fsck not done   Root device is    mounted read-only..." error. When I type "Exit", it continues starts normally.
If you are not holding down the s key while booting then your NVRAM has a flag set or the keyboard has failed and is signaling that the key is pressed.

Try disconnecting USB keyoard at boot or resetting the NVRAM so that the normal boot proceeds.

Should that not work, you'll have to proceed with an odd-ball article followed by the general "Mac fails to start" article:


http://support.apple.com/kb/TS4376
http://support.apple.com/kb/TS2570