Question

I’m looking for a way to update the credentials on existing scheduled tasks on machines.

• Schtasks doesn’t work for AT created scheduled tasks
• Win32_ScheduledJob only works for AT created jobs
• Schedule.Service COM object – not sure

It appears that I can use RegisterTask and RegisterTaskDefinition to CREATE scheduled tasks but I’m not clear if I can update the existing credentials with those methods. Please advise. Thx.

Answer 1

I would recommend having a look at the managed TaskScheduler API, which is a .NET wrapper for the TaskScheduler COM API. It’s an open-source project available on CodePlex.

http://taskscheduler.codeplex.com/

The project author has this to say about updating passwords:

If you are trying to create a task using the credentials of the
current user and you only want it to run when that user is logged in,
you need to call the RegisterTaskDefinition method as in the end of
the Complex example with the InteractiveToken parameter. If you need
to create as another specific user, then use that same method, but
supply the username, password, and set the TaskLogonType to
InteractiveTokenOrPassword or Password. There are some triggers that
are specific to a user, like the LogonTrigger where you can also
supply a user credential.

The appropriate overload for RegisterTaskDefinition is defined in TaskFolder.cs.

http://taskscheduler.codeplex.com/SourceControl/changeset/view/75611#19440

public Task RegisterTaskDefinition(string Path, TaskDefinition definition
   , TaskCreation createType, string UserId, string password = null
   , TaskLogonType LogonType = TaskLogonType.S4U, string sddl = null)