Hibernate feature gets disabled if you select the Hibernation File Cleaner in Windows Vista Disk Cleanup tool. (REF KB928897.) To prevent accidental deletion of the hibernation file from any admin level user account in your system, you may remove the entry Hibernation File Cleaner from the Disk Cleanup options.
Use these steps:
1. Click Start, type Regedit.exe and press ENTER
2. Navigate to the following location:
3. From the File menu, choose Export and backup the branch to a REG file.
4. Right-click the branch Hibernation File and click Delete
5. Exit the Registry Editor.
Download hibercln.zip. Unzip and extract the files to a folder, and run the file hibercln_remove.reg. To add the option back, run the file hibercln_add.reg.
If you inadvertently removed the Hibernation feature earlier using Disk Cleanup, run the following command from an elevated Command Prompt window to restore the Hibernation feature back: