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Task Scheduler and AT Account Issues

This document describes issues with task scheduling and Internet Explorer 5 and above that support staff should be aware of to avoid unintentional service failures.



AT - A command-line utility for Windows NT 4 and Windows 2000 servers that allows you to schedule tasks that use the SYSTEM account.
GUI - Graphical User Interface
Task Scheduler - A scheduling program available from the Control Panel –
Scheduled Tasks that forces you to use credentials and does not let you specify the SYSTEM account.
WinAT- A GUI version of AT that is available in the Resource Kit for NT.


SYSTEM account preferred

It is recommended that you always use the SYSTEM account for scheduled tasks (services) unless you absolutely have to have different credentials (that is, an account other than SYSTEM). You should be able to use the SYSTEM account for any processing that stays local to a single server. However, if you have a job that needs to transfer files between systems, then you will need to specify a credential (some specific account) that can access both systems. This could be a domain account or simply a local service account that exists with the same username and password on each system. That effectively creates pass-through authentication.

Task Scheduler

Forces use of credentials

Task Scheduler forces you to use credentials. You cannot select the SYSTEM account when you schedule a task.

Backward compatible with AT

Task Scheduler is backward compatible with AT. This means that you can display and change tasks with Task Scheduler that you originally scheduled with AT. However, doing so converts them to Task Scheduler jobs, which cannot use the SYSTEM account.

Automatic conversion on display of Properties 

When you display the Properties of an AT- or WinAT-created task in Task Scheduler, it converts the task to Task Scheduler format. In the conversion process, it destroys your selection of the SYSTEM account. 

Even if you click Cancel to exit from the Properties window, Task Scheduler has already undone the SYSTEM account selection. So when the task runs, it fails.

Internet Explorer 5 and WinAT

If you have Internet Explorer 5 or above and you want your scheduled tasks to use the SYSTEM account, you MUST use WinAT (or AT) to set them up. WinAT is recommended rather than AT because of its GUI features.

If you have to change your task schedule, use the WinAT Service Account Configuration window rather than Task Scheduler.



Display current schedule

When you run WinAT, it displays the current schedule. Example:

Add new job to the schedule

To add a new job to the schedule:

1. Click Edit, then Add.
2. Enter job information and click OK. Example:


Display command syntax

To display command syntax, run AT with the /? parameter.

Display job schedule

Example of a command to display job schedule: