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Blinking Question Mark at Startup in Mac OS

Explains reasons and fixes for the blinking question mark on a Mac.

You turn on your Macintosh computer and it boots to a screen showing a single folder with a blinking question mark.

The flashing question mark indicates that the computer cannot locate valid system software. Typically, blinking question marks are caused by:

    • Damaged or missing system software
    • Third Party software conflict
    • External devices
    • Corrupted PRAM

To correct the problem, try the following procedures:

Boot with Extensions Off

Restart the computer and immediately press and hold down the Shift key on the keyboard as it boots up. If it boots successfully with extensions off, this indicates an extension conflict. For information on resolving extension conflicts, see http://support.apple.com/kb/HT2976?viewlocale=en_US.

Re-bless the System Folder

Insert the Software Install CD into the drive (also known as Mac OS CD or System Software CD, but not the Restore CD), restart the computer, and hold the C key down as it boots up. The computer will then attempt to boot from the Software Install CD. If the computer boots successfully from the Software Install CD, the System Folder on the hard drive may need to be "re-blessed." This helps the computer recognize which System Folder to use.
To "re-bless" the System Folder:
  1. Make sure your computer is booted from the Software Install CD.
  2. Double-click on the hard drive.
  3. Double-click on the System Folder
  4. Double-click the System file. (It looks like a suitcase.) If you are unable to open the System file, you may need to reinstall the system software.
  5. After the System file opens, close the System and System Folder windows and restart the computer.
If the above doesn't work:
  1. Boot up your computer using the Software Install CD.
  2. Drag the System file out of the System Folder to another location on your hard disk (the Desktop is locked).
  3. Close the System Folder.
  4. Put the System file back into the System Folder and restart your computer.

Disconnect External Peripherals

Turn off the computer and disconnect all external devices, such as printers, scanners, Zip and CD-ROM drives, modems, hubs, etc. Only the monitor, keyboard, and mouse should be connected. If the computer boots successfully, try adding the devices back one by one to narrow down the source of the problem.

Reset the PRAM

The PRAM (Parameter RAM) may have become corrupted.