Windows 8 Release Preview users find an option to turn fast startup on or off in the power options control panel applet. Fast startup, also known as hybrid boot, basically prepares the system for a faster startup the next time by moving important system files into the hiberfil.sys file so that they can be loaded faster during the next system boot.
This only works when you shut down the system, and is activated by default. It appears that Microsoft seems to have removed the option in the Windows 8 RTM, giving users no option in the control panel to control the fast startup feature.
It can happen that fast startup may cause the operating system to run check disk verifications during startup on dual boot systems, which is why it is usually suggested to turn fast boot off on multi-boot Windows installations.
You need to modify two entries in the Registry to turn off Fast Boot in the final version of Windows 8. Open the Windows Registry editor with Windows-r, enter regedit and hit enter, or enter regedit on the new start page of the operating system and select the Registry editor this way.
- Navigate to the key HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\Power
- Locate the key HiberbootEnabled and double-click on it
- Set the value of the key to 0 to deactivate fast boot
- To restore the setting at a later time, change it back to 1.
- Navigate to the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Power
- Locate HiberbootEnabled there and double-click the entry
- Change the value of the key to 0 to deactivate Fast Boot.
- To restore the key to its original value at a later time, set it back to 1
Windows 8 from the next restart on will no longer use Fast Boot when the system is shut down. Again, I’d only recommend to turn fast boot off if you are noticing issues with check disk during startup. If you are dual booting Windows 7 and 8 for instance, and not noticing any issues, then it is not recommended to turn the feature off. (via Deskmodder)