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If you use the Windows XP’s Hibernation
feature on your laptop, you may want to delete the Hiberfil.sys
file from the hard disk before defragmenting. When you put your
computer in hibernation, Windows XP writes all memory content to
the Hiberfil.sys file before shutting down the system. Then, when
you turn your computer back on, the OS uses the
Hiberfil.sys file to put everything back into memory, and the
computer resumes where it left off. However, Windows XP leaves the
Hiberfil.sys file on the hard disk, even though it’s no longer

The Hiberfil.sys file, which can be very large,
is a special system file that Disk Defragmenter cannot defragment.
Therefore, the presence of the Hiberfil.sys file will prevent Disk
Defragmenter from performing a thorough defragmenting

Follow these steps to remove the Hiberfil.sys
file from the hard disk:

  1. Access the Control Panel and double-click
    Power Options.
  2. Select the Hibernate tab in the Power Options
    Properties dialog box.
  3. Clear the Enable Hibernation check box and
    click OK.

As soon as you clear the check box, Windows XP
automatically deletes the Hiberfil.sys file from the hard disk.
Once you complete the defrag operation, you can re-enable the
Hibernation feature.