The Windows Vista Cleanup tool enables you to clear your disk of unnecessary files. However, as I found out, if you check the hibernation file cleaner box for removal, you will no longer see the ‘Hibernate’ option in Power Options after the Disk Cleanup.
This affected not only Sleep Mode, but also my Backup Power Supply Unit, both of which were unable to save my work in the event of a blackout.
I found this handy kb at Microsoft.
Article ID: 928897
Last Review: March 15, 2007
Revision : 1.2
The hybrid sleep feature and the hibernation feature in Windows Vista may become unavailable after you use the Disk Cleanup Tool
SYMPTOMS
After you use the Disk Cleanup Tool in Windows Vista, you may experience the following symptoms:
- You cannot see the Hibernate option in Power Options.
- When you use the sleep feature, the computer does not recover its settings if power is lost.
CAUSE
This problem occurs when the Disk Cleanup Tool disables the hibernation file. The hibernation file must be enabled to access the hybrid sleep feature and the hibernation feature in Windows Vista.
When the hibernation file is disabled, and the hybrid sleep feature is enabled, a backup of open programs and open files will not be saved to the disk when you use the sleep feature in Windows Vista. Additionally, if the computer loses power while the Windows is in sleep mode, open programs and open files will not be recovered, and any unsaved work will be lost.
RESOLUTION
To resolve this problem in Windows Vista, run the powercfg -h on command at a command prompt to enable the hibernate feature and the hybrid sleep feature. To run this command, follow these steps:
1. Click Start, click All Programs, and then click Accessories.
2. Right-click Command Prompt, click Run as administrator, type powercfg -h on, and then press ENTER.
http://support.microsoft.com/kb/928897/
© 2007 Microsoft Corporation. All rights reserved.
Worked like a charm, however you will not see a confirmation message to indicate whether or not you were successful.
A simple way to check: Control Panel > Power Options > Change Advanced Power Settings.
Hibernate should be back in the Sleep menu.