Task Scheduler

published: August 12, 2019 author: Tinu tags: PowerShell categories: System-Engineering

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Table of Contents

• Table of Contents
• Task Scheduler
  • Create a PowerShell Script
  • Create a new task action
  • Create a new trigger
  • Create new task principal
  • Create new task settings
  • Register the Scheduled Task
  • Register a Scheduled Task as User
  • Delete a Scheduled Task
  • Task Actions
  • Task Information
• Troubleshooting
• Task Scheduler Errors
• See also

Task Scheduler

Create a PowerShell Script

# Create the script
$ScriptFullname = 'C:\Temp\Maintenace\RebootOnce.ps1'
if(-not(Test-Path $ScriptFullname)){$null = New-Item -Path $ScriptFullname -ItemType File -Force}

$Content = @'
"Last boot: $(Get-Date)" | Add-Content "C:\Temp\Maintenace\boot.log"
'@
$Content | Out-File -FilePath $ScriptFullname -Encoding utf8 -Force

Create a new task action

The Task Action is the action or program, that schould be executed.

$taskAction = @{
    Execute  = '%SystemRoot%\system32\WindowsPowerShell\v1.0\powershell.exe'
    Argument = "-NoProfile -NoLogo -NonInteractive -ExecutionPolicy Bypass -File $($ScriptFullname)"
}
$ScheduledTaskAction = New-ScheduledTaskAction @taskAction

Create a new trigger

The Trigger define the runtime of the action.

Parameters:

• AtLogOn – Runs the task when a user logs on
• AtStartup – When the system is started
• At – Used with Once, Daily, or Weekly. Defines the specific time to run the task
• Daily – Runs every day. Define the days with DaysOfWeek
• DaysInterval – Run every x days
• DaysOfWeek – This can be used with Daily or Weekly. Defines which days to run the task
• Weekly – Runs the tasks every week
• WeeklyInterval – Determines the interval between the weeks.

$taskTrigger = @{
    AtStartup = $true
}
$ScheduledTaskTrigger = New-ScheduledTaskTrigger @taskTrigger

Create new task principal

Specifies the security context in which a task runs.

Parameter LogonType:

Specifies the security logon method that Task Scheduler uses to run the tasks that are associated with the principal.

The acceptable values for this parameter are:

• None
• Password
• S4U
• Interactive
• Group
• ServiceAccount
• InteractiveOrPassword

For more information about LogonType values, see Principal.LogonType

$taskPrincipal = @{
    UserID    = 'NT AUTHORITY\SYSTEM'
    LogonType = 'ServiceAccount'
    RunLevel  = 'Highest'
}
$ScheduledTaskPrincipal = New-ScheduledTaskPrincipal @taskPrincipal

Create new task settings

Settings for the Task.

Parameters:

• DisallowDemandStart
• DisallowHardTerminate
• Compatibility
• DeleteExpiredTaskAfter
• AllowStartIfOnBatteries
• Disable
• MaintenanceExclusive
• Hidden
• RunOnlyIfIdle
• IdleWaitTimeout
• NetworkId
• NetworkName
• DisallowStartOnRemoteAppSession
• MaintenancePeriod
• MaintenanceDeadline
• StartWhenAvailable
• DontStopIfGoingOnBatteries
• WakeToRun
• IdleDuration
• RestartOnIdle
• DontStopOnIdleEnd
• ExecutionTimeLimit
• MultipleInstances
• Priority
• RestartCount
• RestartInterval
• RunOnlyIfNetworkAvailable
• CimSession
• ThrottleLimit
• AsJob

$taskSettings = @{
    ExecutionTimeLimit = (New-TimeSpan -Hours 1)
}
$ScheduledTaskSettingsSet = New-ScheduledTaskSettingsSet @taskSettings

Register the Scheduled Task

$registerTask = @{
    TaskName    = "BootLog"
    Description = "Log the last boot time"
    Action      = $ScheduledTaskAction
    Trigger     = $ScheduledTaskTrigger
    Principal   = $ScheduledTaskPrincipal
    TaskPath    = '\Maintenace'
    Settings    = $ScheduledTaskSettingsSet
}
Register-ScheduledTask @registerTask

Get-ScheduledTask -TaskName "RestartOnce" | Select *

Get-ScheduledTask "RestartOnce" | Get-ScheduledTaskInfo | Select *

Register a Scheduled Task as User

Running the Task with Different Privileges. (Have to test the differences between this and New-ScheduledTaskPrincipal)

$Credentials = Get-Credential

$registerTask = @{
    TaskName    = "BootLog"
    Description = "Log the last boot time"
    Action      = $ScheduledTaskAction
    Trigger     = $ScheduledTaskTrigger
    TaskPath    = '\Maintenace'
    User        = $Credentials.UserName
    Password    = $Credentials.GetNetworkCredential().Password
    RunLevel    = 'Highest'
}

Register-ScheduledTask @registerTask

Delete a Scheduled Task

# Delete the new PowerShell scheduled task
Unregister-ScheduledTask -TaskName "RestartOnce" -Confirm:$false

Task Actions

Action: Start a program

Program/script: %SystemRoot%\system32\WindowsPowerShell\v1.0\powershell.exe

Add arguments: -NoProfile -NoLogo -NonInteractive -ExecutionPolicy Bypass -File "C:\Temp\MyScript.ps1"

Task Information

Get-ScheduledTask | Where-Object TaskName -match "Verify Summary" | ForEach {

    $Task = $_
    $TaskInfo = Get-ScheduledTaskInfo -TaskName $Task.TaskName

    [PSCustomObject]@{
        TaskName           = $Task.TaskName
        TaskPath           = $Task.TaskPath
        Author             = $Task.Author
        Date               = $Task.Date
        Description        = $Task.Description
        State              = $Task.State
        LastRunTime        = $TaskInfo.LastRunTime
        NextRunTime        = $TaskInfo.NextRunTime
        LastTaskResult     = $TaskInfo.LastTaskResult
        NumberOfMissedRuns = $TaskInfo.NumberOfMissedRuns
    }

}

TaskName           : Verify Summary
TaskPath           : \
Author             : Domain\Asscount
Date               : 2019-08-12T09:04:50.0000171
Description        :
State              : Ready
LastRunTime        : 12.08.2019 09:08:08
NextRunTime        : 19.08.2019 08:04:04
LastTaskResult     : 0
NumberOfMissedRuns : 0

Troubleshooting

Start the PowerShell-Script with a CMD-Script, to verify that the script can be run with the configured Account in the ScheduledTask.

@echo off
rem ---------------------------------------------------------------------------- *
rem Description: Start PS-Script
rem Author     : Martin Walther
rem ---------------------------------------------------------------------------- *

rem Path: %~dp0 Script: %~n0
set log=%~dp0%~n0.log
set script=%~dp0%~n0.ps1
echo %log%
echo %script%

echo Start %script% %date%%time% > %log%
%SystemRoot%\system32\WindowsPowerShell\v1.0\powershell.exe -NoProfile -NoLogo -NonInteractive -ExecutionPolicy Bypass %script% >> %log%
echo End %script% %date%%time% >> %log%

In the Logfile, you can find any Errors- or Output from the PowerShell-Script.

Task Scheduler Errors

Error	Problem	Solution
0x1	Path to the program does not exists	Correct the Path to the program e.g. change powershell.exe to C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
0xFFFD0000	Path to the script does not exists	Correct the Path to the script

See also

Task Scheduler Error and Success Constants on Microsoft Docs.

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