If your Mac is starting or running slower than it used to, gives you error messages during boot, or takes longer and longer to boot, you might have a pending hard drive failure. While you can still access your hard disk, you need to run a hard drive utility program. If your situation is worse than that, such as the hard drive won’t start or mount, you may need help from a third-party Mac hard drive recovery program.
While your hard disk is still working
You can perform Mac hard drive recovery operations while your computer is still running in single-user, normal session, or boot-up (but no desktop displays) modes. In fact, it is a good idea to get familiar with the use of hard drive recovery operations, so that you are familiar with how they work. When the time comes to really make use of them, you’ll be ready.
Your Mac comes with a couple of utilities that you can access either using the installation disk or the command line – Disk Utility and fsck. The utility fsck is used at the command line and should not be used first if you are running Mac OS x 10.4 or later. Disk Utility is accessed from the command line using the command diskutil or hdiutil.
The graphical version of Disk Utility is accessed from your installation disk. The utility gives you broad support for hard disk and data issues on your drive. The hard drive recovery features of disk utility include:
- Verification and reparation of disk integrity compromises
- Verification and reparation of corrupted permissions
- Reconciliation of the Apple partition table with the GUID partition table and the Master Boot Record
- Reparation of mount, unmount and ejection of disks for all media
- Restoration of volumes from Apple Software Restore (ASR) images
- Running the Self Monitoring Analysis and Reporting Technology (SMART) tool (which can direct you to return the drive to the manufacturer for an applicable warranty replacement)
- Additional functions related to hard disk and CD images and more
All hard disk recovery options on the disk utility should be used to confirm that the disk is properly maintained and restored. See Apple’s support page on Disk Utility.
For the fsck command line utility, use this only when your ability to start a normal session is compromised. While your disk is healthy, look up the limitations and use of fsck or use another computer system to do so to understand the command line use needed to determine how your drive is configured prior to using this utility.
When you cannot boot
A power loss event, an improper shutdown, or a forced restart of your Mac can result in an inability to start a session. When that happens, or when your computer partially boots, cannot get to the login screen or cannot display the desktop, you might try a safe boot.
Safe boot is an option at startup shown for Mac OS x 10.2 or later. This mode includes automatic disk checking and repair. You might find your computer is fully restored after the safe boot when you shut down and restart normally. If your Mac OS x is earlier than 10.2, you should use Disk Utility instead.
Guest post by David Ritchie