Hibernation mode is supported by Windows Vista and Windows XP only for up to and including 4GB of memory.

Hibernation mode is disabled by Windows if the computer has more than 4GB of memory. Additionally, the Hibernation tab in the Power Options Properties window is not present.

Hibernation mode saves the contents of the computer's memory to the hard disk drive, when the computer is turned off. When the computer is turned on again, the data stored on the hard disk drive is restored to memory.

For further information about Hibernation mode not working with more than 4GB of memory, see Microsoft's Knowledge Base article 888575 You cannot put a computer that has more than 4 GB of memory into hibernation in Windows XP, in Windows Server 2003, in Windows Vista, or in Windows Server 2008 .

If you wish to use Hibernation mode, and your computer has more than 4GB of memory, you must reduce the computer's total memory size to 4GB or less. See the User's Guide for your model for instructions on removing and installing memory.

For Windows Vista, you must also re-enable Hibernation mode, by following the steps below. You will need an administrator-level password.

1. Log in as an administrator.

2. Click Start, type cmd in the Start Search text box, right-click cmd.exe, click Run as administrator, and then click Continue.

3. At the command prompt, type powercfg -h on, then press Enter.

After you have decreased the computer's memory to 4GB or less, if the Hibernate tab does not reappear in the Power Options Properties window, add the /MAXMEM=4096 switch to the Boot.ini file. For more information about the /MAXMEM switch see Microsoft's Knowledge Base article 108383 The /maxmem switch in the Windows Boot.ini file. Be very careful editing the Boot.ini file, as an error in this file's contents can prevent the computer from starting Windows.

The Hibernate tab in the Power Options Properties window can be accessed by clicking Start, and then Run. Type powercfg.cpl, and then click OK.

^{- km/wa}