Computer with Uninterruptible Power Supply Does Not Start After Power Loss Even After AC Power Is Restored (819038)


The information in this article applies to:

  • Microsoft Windows Server 2003, 64-Bit Datacenter Edition
  • Microsoft Windows Server 2003, 64-Bit Enterprise Edition
  • Microsoft Windows Server 2003, Datacenter Edition
  • Microsoft Windows Server 2003, Enterprise Edition
  • Microsoft Windows Server 2003, Standard Edition
  • Microsoft Windows Server 2003, Web Edition
  • Microsoft Windows XP Home Edition
  • Microsoft Windows XP Professional
  • Microsoft Windows Small Business Server 2003, Standard Edition
  • Microsoft Windows Small Business Server 2003, Premium Edition

SYMPTOMS

Some computers that have an uninterruptible power supply (UPS) may not start after the UPS shuts off the computer after a power loss, even when the main alternating current (AC) power supply is restored.

CAUSE

This problem occurs when the BIOS setting for system behavior after power restoration is Stay Off, or when the value of the Last State setting is Stay Off. When the BIOS setting is Last State and the system shuts down without pausing at the "It is now safe to power off your computer" message, the value of the Last State setting defaults to Stay Off. When this behavior occurs, the system does not restart even after the power is restored from the UPS.

Note These setting names may not be the same for your computer's BIOS settings. Contact your computer manufacturer for details about the BIOS settings on your computer.

WORKAROUND

To work around this issue, configure the BIOS settings so that the computer always starts when the AC power supply is restored.

MORE INFORMATION

The BIOS of most computers contains the equivalents of the following settings: Always On, Always Off, and Last State in the "After AC Power Supply Fails" section of the BIOS settings. These settings generate the following behaviors when the main AC power supply is restored:
  • Always On: The computer starts.
  • Always Off: The computer stays off.
  • Last State: The computer returns to the last state of AC power.
Note Not all computers have these settings or use the same names for these settings. Contact your computer manufacturer for details about the BIOS settings on your computer.

When a program calls the ExitWindowsEx() function with EWX_SHUTDOWN to shut down the computer, some computers may not start up even after the power is restored from UPS. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

819037 Computer Powers Off Unexpectedly If a Program Calls the ExitWindowsEx() Function

Modification Type:MajorLast Reviewed:3/1/2004
Keywords:kbprb KB819038 kbAudITPRO
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