Windows 7 cannot be upgraded to SP1 if the computer is disconnected from AC power

Applies to: Windows 7 UltimateWindows 7 EnterpriseWindows 7 Professional

The installation of Windows 7 Service Pack 1 (SP1) cannot start because the GetSystemPowerStatus function detects that the computer is not connected to AC power, and then it returns a CBS_E_AC_POWER_REQUIRED (0x800f0829) failure that blocks the installation.

How to obtain this update

Windows Update

This update is available from Windows Update.

Update detail information


There is no prerequisite to install this update.

Registry information

To apply this update, you do not have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this update.

Update replacement information

This update does not replace a previously released update.

More Information


See the terminology that Microsoft uses to describe software updates.