NOTE: These methods work best for systems that have a large amount of memory (RAM).


1. Hibernation Reserved Space

Hibernation reserves HD space up to the amount of memory your system has. To disable hibernation and recover that drive space then type the following command with administrator privileges in cmd.exe.

powercfg -h off

2. Decrease Virtual memory

Similarly to hibernation the system page file or virtual memory also reserves HD space up to the amount of memory your system has. This shouldn’t every be disabled, but you can reduce it to a more reasonable size especially if you have over 4GB of memory. Follow the steps bellow.
  • Right click “Computer” and click “Properties”
  • Click on “Advanced system settings” in the left column
  • In the “Performance” section, click on “Settings”
  • Go to the “Advanced “ tab
  • In the “Virtual Memory” section click on “Change”
  • Uncheck “Automatically manage paging File size for all drives”
  • Chose the “Custom size” radial button
    • set the “Initial size (MB):” to 512
    • set the “Maximum size (MB):” to 1024
  • Restart your computer for changes to take effect

3. Remove Service Pack 1 backups Thanks Alan McBurney

After installing Service Pack 1 about 4GB are used to maintain backup files. If you are certain that you will never need to revert back before SP1 then you can free up this space by typing the following command with administrator privileges in cmd.exe.

DISM /online /Cleanup-Image /SpSuperseded