How can I run a PowerShell task at logon and repeat it every three minutes?

If the script is meant to run continuously, you could start it once at logon and have the script perform its work inside a loop with Start-Sleep -Seconds 180. However, a long-running loop can be less manageable than a scheduled task, and a service may be more appropriate if this needs to run reliably in the background.

The built-in trigger parameters don’t let you combine -AtLogOn with an indefinite repetition interval. One option is to create the task in the graphical Task Scheduler first, configure the logon trigger and repetition there, and then export or inspect the resulting XML. You can use that XML when registering the task from PowerShell.

You can construct the repetition pattern yourself and assign it to the logon trigger’s Repetition property. For example, create the trigger with New-ScheduledTaskTrigger -AtLogOn, then create an MSFT_TaskRepetitionPattern CIM instance with an interval such as [System.Xml.XmlConvert]::ToString((New-TimeSpan -Minutes 3)) and assign it to $trigger.Repetition before registering the task.

Another practical approach is to create an ordinary one-time trigger whose repetition interval is three minutes, then copy its Repetition property onto the logon trigger: $logonTrigger = New-ScheduledTaskTrigger -AtLogOn; $repeatTrigger = New-ScheduledTaskTrigger -Once -At (Get-Date) -RepetitionInterval (New-TimeSpan -Minutes 3) -RepetitionDuration ([TimeSpan]::MaxValue); $logonTrigger.Repetition = $repeatTrigger.Repetition. Register the task using $logonTrigger.