1, out of this error is because the Mac OS system internal file system in the verification error, as long as the Mac reboot, please hold down the keyboard on the Command+s key, into the safe mode, you can solve, if not a successful we may try many times, anyway, until the success.
2, and then into the safe mode, in the open screen will have all the English in the beating, and so on it after we press the keyboard "enter" button, appear command prompt, as shown in the figure
3, then we in the command mode Input fsck-f command, after the loss and then press "enter" key to execute the command.
4, enter the system will automatically enter the repair file state, how long it takes to see the speed of the hard disk of our computer, as shown in the picture
5, when the repair is complete and see the screen prompts "the volume Macintosh HD was reaired successfully", the description has been successful, as shown in the figure
6, all right, we'll enter the reboot command, and then we'll restart the computer.
7, after the reboot we will find that your computer no longer prompts failed to modify the partition map, because the file system validation failure problem.