MSU IT Techbase

Using DiskWarrior to repair problems on MacOS X computers - TB4264

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The "question mark" or "flashing folder" icon in the center of the display on Macintosh computer bootup, is a sign that either the system software, or the hard drive, is damaged; a "spinning wheel/spinning beachball" that lasts far longer than normal, is also a sign. Other indications that the MacOS or hard drive needs repair include but are not limited to: random/frequent application or computer crashes; question mark or flashing "circle/slash" on startup; gray screen freezes; or a general inability to properly boot up the Mac.

If the Mac having any of these problems can boot from the OS CD by holding the C key down when booting, it can sometimes be fixed by running Apple's Disk First Aid (MacOS 9.2.2 and previous) or Disk Utility (OS X versions). In many cases, however, the MacOS utility software cannot resolve these issues. Reformatting the system and/or reinstalling the MacOS may need to be used as a last resort option, where possible.

Alsoft DiskWarrior is the tool IT Services Support uses most often to diagnose and repair MacOS X computers experiencing problems. DiskWarrior attempts to fix these problems by repairing and replacing the Mac's directory database. More info on DiskWarrior and its uses can be found at

Note that if a Mac having the problems described above won't boot from its OS CD, the drive is most likely damaged, and the hardware may need servicing. We recommend you bring your computer to the MSU Help and Repair Center, 120 Computer Center to have the computer evaluated.

The instructions below explain how to boot from and use the Alsoft DiskWarrior CD on MacOS X computers.

NOTE: DiskWarrior 4.0 will not work on pre-G3 processors. If your Mac is running MacOS 9.2.2 or earlier, DiskWarrior 2.1 is available for purchase directly from Alsoft.

If running Disk Utility from the MacOS X CD/DVD does not resolve the issue with your computer, an IT Services Consultant will need to refer you to a repair facility for further assistance.

Boot from the CD

Place the CD in the CD (or DVD) drive and start the machine. If it is powered on, reboot it after placing the CD in the drive.

There are two ways to boot DiskWarrior from the CD:

  1. Hold the C key down until the computer boots into DiskWarrior.
    • Note: this may take a long time.
  2. Hold the option key down until you see the boot menu. The boot process should happen almost immediately. When this boots, wait for the watch to stop spinning, then select the CD drive title ("DiskWarriorCD") and then click the right arrow ("->") to continue loading the CD.
    • Note: this option will be faster to boot, but takes longer once the CD is chosen from the menu.

In addition to the option key being the faster boot process, it also allows you to see fairly immediately whether the computer's hard drive (usually named "Macintosh HD") is viewable.

Note: Either method will take at least 10 minutes to boot from the CD.

If DiskWarrior cannot see the hard drive, it can't repair it, and the computer's hard drive needs to be replaced by an Apple Certified Service Provider, such as the MSU Computer Help and Repair Center. Warm-boot the computer by holding down control-apple-power, then immediately hold down the mouse button to eject the CD.

Graph the errors on the drive

Once DiskWarrior boots, select the drive that you wish to fix and click the "Graph" button to view the errors that exist on the drive. Make special note of the percentage of errors that the drive contains.

Rebuild the drive

With the drive to be fixed selected, click the "Rebuild" button.

View the details

When the rebuild finishes, click on the "Details" button to view what (if any) changes have occurred.

Replace the disk contents with the rebuilt version

After you have reviewed the changes, click on the "Replace" button. DiskWarrior will attempt to replace the contents of the drive with the fixed one.

It is possible that DiskWarrior may not fix the issue. There are a few scenarios that may occur:

  • If the computer cannot boot from the CD, this indicates a problem DiskWarrior can't repair (i.e., the drive may be bad, or the OS isn't supported by the CD).
  • If the drive had over 30% of errors on it, DiskWarrior may not be able to fully fix the issue.
  • DiskWarrior may be unable to fix the issues for any number of unknown reasons.
  • DiskWarrior may repair the drive, but was unable to resolve the primary problem with the computer.

If rebuilding the drive fixes the issue, remove the CD from the drive and reboot as normal.

Perform File Operations

You can also click on the File section. From this section you can repair the disk permissions and also check the files and folders of the drive for damage or potential problems.

These tasks should be performed after rebuilding the directory.

Removing the CD

If you can't boot into the operating system to remove the CD, it can be removed by holding down the mouse button while the computer tries to boot. Just press and hold the mouse button as soon as you turn the computer on. Once the CD comes out, you can let go of the button.

Purchasing DiskWarrior

If you are a MacOS X user and do not own DiskWarrior, IT Services Support strongly advises that you purchase a copy for yourself. Alsoft DiskWarrior 4.0 or greater can be purchased from the MSU Computer Store (517-432-0700) or from Alsoft directly by going to Before purchasing, be sure to check for possible compatibility issues with your OS version or computer model.

Keywords for this Document

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Date Last Modified: 1/22/2016 12:59:24 PM

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