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Troubleshooting Task Scheduler

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Applies To: Windows Server 2008, Windows Vista

If you are having problems scheduling tasks or getting tasks to run correctly, first ensure that the Task Scheduler service is running. You can verify the service is running if you click the Start button, click Control Panel, click System and Maintenance, click Administrative Tools, and then click Services and verify that the Task Scheduler service's status is Started.

Note

The Task Scheduler service cannot be used while the computer is running in safe mode.

Updated troubleshooting information may be available online at Troubleshooting Task Scheduler.

For information about an event or error message related to Task Scheduler, see Events and Error Message Center.

A task does not run when you expect it to run

If a scheduled task does not run when you expect it to run, ensure that the task is enabled, and also check the triggers on the task to ensure that they are set correctly. For more information see, Enable a Task to Run. For more information about updating a task's triggers, see Change an Existing Task. Also, check the history of the task to see when the task was started and to check for errors. For more information, see View Task Properties and History.

A task will run only if all of the task's conditions are met. You can set a task's conditions on the Conditions tab of the Task Properties dialog box. For more information, see Task Conditions.

Some tasks will only run when a certain user is logged on, depending on a task's security options. If a scheduled task does not run when you expect it to run, ensure that the task's security options are set correctly. For more information, see Task Security Context and Change an Existing Task.

A task ran, but the program that should have been executed did not run correctly

If a task attempts to execute a program, but the program does not run correctly, first try running the program manually (not from a task) to ensure that the program works correctly. You might need to add command-line options to the path of the program. For more information, see Actions. If available, view the help for the program that you are trying to run.

Some programs require elevated privileges to run correctly. If a task is running a program that requires elevated privileges, ensure that the task runs with the highest privileges. You can set a task to run with the highest privileges by changing the task's security options on the General tab of the Task Properties dialog box.

If a task program does not run correctly, check the history of the task for errors. For more information, see View Task Properties and History.

An error occurs when a task attempts to send an e-mail

If a task attempts to send an e-mail, but the e-mail doesn't get sent correctly, first make sure that the settings for the e-mail action on the task are set correctly. The e-mail action must have a valid value for the SMTP server, To, and From settings. For more information about these settings, see Actions.

Make sure the SMTP server that sends the e-mail is setup correctly. E-mail is sent using NTLM authentication for Windows SMTP servers, which means that the security credentials used for running the task must also have privileges on the SMTP server to send e-mail. If the SMTP server is a non-Windows based server, then the e-mail will be sent if the server allows anonymous access.  For information about setting up the SMTP server, see SMTP Server Setup, and for information about managing SMTP server settings, see SMTP Administration.

A task is using 100 percent of the CPU

A task can be scheduled that is triggered often enough to cause 100 percent of the CPU to be used. If this problem occurs, the system can become unusable.

To correct this problem, disable the task and then change the trigger for the task. For more information about how to change a task, see Change an Existing Task.

If the system is unresponsive because the task is using all of the system resources, perform the following steps:

  1. Restart the computer in safe mode (the Task Scheduler service does not run in safe mode),

  2. In the /Windows/System32/Tasks folder, rename the file for the task, or delete the file.

  3. Restart the system in normal mode and then redefine the task.