Scheduled Tasks cannot run with a blank password

After you schedule a task by using the Scheduled Tasks tool, the task may not run at the time you chose. If you view the status of the task, you may receive the following error message:

This behavior can occur if the user account you used when you created the task has a blank (null) password. When you add a scheduled task to your Windows XP-based computer, you must provide a user name and password for the task. If you are using a local user account, the user password cannot be blank.

To resolve this behavior, create a password for the appropriate user account, and then reschedule the task and provide the new password when you are prompted for it. To create a password for a user account:

1. Click Start, click Control Panel, and then double-click User Accounts.
2. Click the user account you want to add a password to, and then click Create a Password.
3. Follow the instructions on the screen to create a password. Note that any valid password is acceptable, but it cannot be a blank password, and you must log off and then log on again before you schedule the task.

This behavior is by design.

This behavior did not exist in versions of Windows that are earlier than Windows XP. To improve system security, any task that is using a local account (non-domain account) as the account under which the scheduled task is to run will require a password. If the local account does not have a password, a password must be created for that account.