- If your Mac computer runs at a deficient speed or shuts down unusually, create a backup or transfer the files to an external storage device first.
- Scan your hard drive for errors using Terminal.
- On your Mac computer, launch the Terminal app from the "Utilities" folder.
- Type the command "diskutil list" in the Terminal window and press the Enter key.
- Type the command "diskutil verifyVolume[drive name]" and press the Enter key (enter your crashed hard drive name inside the [drive name]).
- Type the command "diskutil verifyVolume/" and press the Enter key.
- If it displays the "The volume /dev/rdisk3s1 appears to be OK" message, the hard drive is corrupted.
- If it displays the "The volume Macintosh HD was found corrupt and needs to be repaired" message, then check if you have a backup.
- Once again, type the command "diskutil verifyVolume[drive name]" and press Enter (replace the [drive name] with your crashed hard drive name).
- Now, the crashed hard drive will be repaired automatically.
- If the problem remains unresolved, fix the system consistency with FSCK.