Register-ScheduledTask : The parameter is incorrect.

Code i used:

Code:

If (-NOT ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator))
{
  # Relaunch as an elevated process
  $User = [Environment]::UserName
  $Script = $MyInvocation.MyCommand.Path
  Start-Process powershell.exe -Verb RunAs "-ExecutionPolicy RemoteSigned -File `"$PSCommandPath`" `"${User}`""
  Exit
}

$Action   = New-ScheduledTaskAction -Execute "$PSScriptRoot\LibreWolf-WinUpdater.exe" -Argument "/Scheduled"
$Settings = New-ScheduledTaskSettingsSet -AllowStartIfOnBatteries -DontStopIfGoingOnBatteries -RunOnlyIfNetworkAvailable
$4Hours   = New-ScheduledTaskTrigger -Once -At (Get-Date -Minute 0 -Second 0).AddHours(1) -RepetitionInterval (New-TimeSpan -Hours 4)
$AtLogon  = New-ScheduledTaskTrigger -AtLogOn
$AtLogon.Delay = 'PT1M'
$User     = If ($Args[0]) {$Args[0]} Else {[Environment]::UserName}

Register-ScheduledTask -TaskName "LibreWolf WinUpdater ($User)" -Action $Action -Settings $Settings -Trigger $4Hours,$AtLogon -User $User -RunLevel Highest –Force
Write-Output Done.
[Console]::ReadKey()

Result:

Code:

Register-ScheduledTask : The parameter is incorrect.
(23,8):UserId:
At C:\Program Files\LibreWolf\ScheduledTask-Create.ps1:17 char:1
+ Register-ScheduledTask -TaskName "LibreWolf WinUpdater ($User)" -Acti ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (PS_ScheduledTask:Root/Microsoft/...S_ScheduledTask) [Register-Schedule
   dTask], CimException
    + FullyQualifiedErrorId : HRESULT 0x80070057,Register-ScheduledTask

Why the error? It worked before and it works on my other machine with the same windows version.

Your script breaks when passed an username which doesn't exist locally.

$User = If ($Args[0]) {$Args[0]} Else {[Environment]::UserName

Code:

PS C:\Users\GARLIN\Downloads> .\Untitled1.ps1 NOTREALUSER
Register-ScheduledTask : No mapping between account names and security IDs was done.
(23,8):UserId:
At C:\Users\GARLIN\Downloads\Untitled1.ps1:17 char:1
+ Register-ScheduledTask -TaskName "LibreWolf WinUpdater ($User)" -Acti ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (PS_ScheduledTask:Root/Microsoft/...S_ScheduledTask) [Register-ScheduledTask], CimException
    + FullyQualifiedErrorId : HRESULT 0x80070534,Register-ScheduledTask
 
Done.
Exception calling "ReadKey" with "0" argument(s): "Cannot read keys when either application does not have a console or when console input has been redirected from a file. Try Console.Read."
At C:\Users\GARLIN\Downloads\Untitled1.ps1:21 char:1
+ [Console]::ReadKey()
+ ~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : InvalidOperationException