Scheduled Task with Daily Trigger and Repetition Interval

While the PowerShell interface for scheduled task triggers is limited, it turns out if you set the RepetitionDuration to [System.TimeSpan]::MaxValue, it results in a duration of "Indefinitely".

$trigger = New-ScheduledTaskTrigger `
    -Once `
    -At (Get-Date) `
    -RepetitionInterval (New-TimeSpan -Minutes 5) `
    -RepetitionDuration ([System.TimeSpan]::MaxValue)

Tested on Windows Server 2012 R2 (PowerShell 4.0)

Here is a way of creating a scheduled task in Powershell (v5 on my machine, YMMV) that will start at 12AM every day, and repeat hourly for the rest of the day. Therefore it will run indefinitely. I believe this is a superior approach vs setting -RepetitionDuration to ([timespan]::MaxValue) as I commented earlier, as the trigger will show up in the Task Scheduler as:

At 12:00 AM every day - After triggered, repeat every 30 minutes for a duration of 1 day.

Rather than the date on which the task was registered appearing in the trigger as approaches that use -Once -At 12am result in, create the trigger as a simple -Daily -At 12am, register the task then access some further properties on the tasks Triggers property;

$action = New-ScheduledTaskAction -Execute <YOUR ACTION HERE>
$trigger = New-ScheduledTaskTrigger -Daily -At 12am
$task = Register-ScheduledTask -TaskName "MyTask" -Trigger $trigger -Action $action
$task.Triggers.Repetition.Duration = "P1D" //Repeat for a duration of one day
$task.Triggers.Repetition.Interval = "PT30M" //Repeat every 30 minutes, use PT1H for every hour
$task | Set-ScheduledTask
//At this point the Task Scheduler will have the desirable description of the trigger.

I'm sure there must be a better way, but this is my current workaround.

I created a task with the triggers I wanted then grabbed the XML it generated.

Below I am creating the task, then pulling the XML for that new task, replacing my triggers, then un-registering the task it and re-registering it with the updated XML.

Long term, I will probably just use the full XML file for the task and replace the strings as needed, but this works for now.

#Credentials to run task as
$username = "$env:USERDOMAIN\$env:USERNAME" #current user
$password = "notmypass"

#Location of Scripts:
$psscript = "C:\test\test.ps1"
$Sourcedir ="C:\testsource\"
$destdir = "C:\testdest\"
$archivepassword = "notmypass"

####### Create New Scheduled Task
$action = New-ScheduledTaskAction -Execute "Powershell" -Argument "-WindowStyle Hidden '$EncryptSync' '$sourcedir' '$destdir' '$archivepassword'"
$trigger = New-ScheduledTaskTrigger -Once -At 7am -RepetitionDuration  (New-TimeSpan -Days 1)  -RepetitionInterval  (New-TimeSpan -Minutes 30)
$settings = New-ScheduledTaskSettingsSet -Hidden -AllowStartIfOnBatteries -DontStopIfGoingOnBatteries -StartWhenAvailable -RunOnlyIfNetworkAvailable
$ST = New-ScheduledTask -Action $action -Trigger $trigger -Settings $settings
Register-ScheduledTask "EncryptSyncTEST" -InputObject $ST -User $username -Password $password


[xml]$EncryptSyncST = Export-ScheduledTask "EncryptSyncTEST"
$UpdatedXML = [xml]'<CalendarTrigger xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task"><Repetition><Interval>PT30M</Interval><Duration>P1D</Duration><StopAtDurationEnd>false</StopAtDurationEnd></Repetition><StartBoundary>2013-11-18T07:07:15</StartBoundary><Enabled>true</Enabled><ScheduleByDay><DaysInterval>1</DaysInterval></ScheduleByDay></CalendarTrigger>'
$EncryptSyncST.Task.Triggers.InnerXml = $UpdatedXML.InnerXML

Unregister-ScheduledTask "EncryptSyncTEST" -Confirm:$false
Register-ScheduledTask "EncryptSyncTEST" -Xml $EncryptSyncST.OuterXml -User $username -Password $password