A scheduled task is suspended unexpectedly, and the operating system resumes sleep when you select the "Wake the computer to run this task" option in Windows Vista or in Windows Server 2008

In Windows Vista or Windows Server 2008, you create a task in Task Scheduler, and then you select the Wake the computer to run this task option. This option makes sure that the computer wakes up from sleep or from hibernation to run the task. In this scenario, the scheduled task wakes up the computer as scheduled. However, 120 seconds later, the operating system resumes sleep or hibernation even if the scheduled task is running. Therefore, the scheduled task is suspended unexpectedly.

Note The issue does not occur if the scheduled task calls the SetThreadExecutionState() function.

To resolve this problem, apply the following hotfix. After you apply the hotfix, when a job that includes the Wake the computer to run this task option starts, Task Scheduler calls the SetThreadExecutionState function to indicate that the Task Scheduler is busy. After the job ends, Task Scheduler calls the SetThreadExecutionState function to clear the ES_CONTINUOUS flag and to reset the system idle timer. Therefore, the system does not resume sleep unexpectedly while the task is running.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the �Hotfix Request� page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Prerequisites

To apply this hotfix on a Windows Vista-based computer, you must have Windows Vista service pack 1 (SP1) installed. For more information, click the following article number to view the article in the Microsoft Knowledge Base: No prerequisites are required for Windows Server 2008-based computers.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista and Windows Server 2008 file information notes

The .manifest files and the .mum files that are installed in each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. These files and their associated .cat (security catalog) files are critical to maintaining the state of the updated component. The .cat files are signed with a Microsoft digital signature. The attributes of these security files are not listed.

For all supported x86-based versions of Windows Server 2008 and Windows Vista

For all supported x64-based versions of Windows Server 2008 and Windows Vista

For all supported IA-64-based versions of Windows Server 2008

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about the SetThreadExecutionState function, visit the following Microsoft Web site: For more information about the Windows Vista Task Scheduler, visit the following Microsoft Web site:For more information about system sleep criteria, visit the following Microsoft Web site:

Additional file information for Windows Server 2008 and for Windows Vista

Additional files for all supported x86-based versions of Windows Server 2008 and Windows Vista

Additional files for all supported x64-based versions of Windows Server 2008 and Windows Vista

Additional files for all supported IA-64-based versions of Windows Server 2008