Technical Zone

To understand why hiberfil.sys exists, we must look at the Windows Hibernate function. When you activate Hibernate, Windows takes a snap shot of your current session (all your running programs, open files, etc.) and writes that information to your hard drive. Hibernate was designed to speedup shut downs and restarts and save power on laptops.

Figure 1: Hiberfil.sys, as the name suggests, is the file to which Windows saves the snap shot data. Thus, the file is always equal in size to the total amount of available RAM on the computer (see Figure 1).

Disabling Windows Hibernation

As I noted earlier, you can manually delete hiberfil.sys, but it will just come back. To permanently remove the file, you must disable the Windows Hibernate function. You can do this through either the Windows GUI or from the command line.

Windows XP

On Windows XP systems, you can easily disable Hibernate through the GUI using the following steps:

Open the Control Panel and access Power Options.
Select the Hibernate tab in the Power Options Properties dialog box.
Clear the Enable Hibernation check box (see Figure 2) and click OK.

On Windows 7 & Vista

How to disable Hibernate from Command prompt
Open a command prompt with administrative privileges.
Enter “powercfg.exe -h off” (see Figure 4).
Exit the command prompt.

–Cheers