Start-Process with -Verb RunAs and SysNative

Question

I'm working on a script where I want to make sure that I am always running in an elevated 64-bit instance of PowerShell.

Given these variables:

$PsPath = "$env:SystemRoot\SysNative\WindowsPowerShell\v1.0\powershell.exe"
$PsArgs = '-ExecutionPolicy', 'Bypass', '-File', $PSCommandPath

Is there any reason why trying to start the process would error out? This is starting from a non-elevated, 32-bit PowerShell process.

PS D:\Intune\Scripts> Start-Process -FilePath $PsPath -Verb RunAs -ArgumentList $PsArgs
Start-Process : This command cannot be run due to the error: The system cannot find the path specified.
At line:1 char:1
+ Start-Process -FilePath $PsPath -Verb RunAs -ArgumentList $PsArgs
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [Start-Process], InvalidOperationException
    + FullyQualifiedErrorId : InvalidOperationException,Microsoft.PowerShell.Commands.StartProcessCommand

If I remove "-Verb RunAs", I get a 64-bit instance, but it is not elevated.

If I use System32 instead of SysNative, I will get an elevated 32-bit instance.

This limitation is not making a lot of sense to me, so any insight is appreciated!

Answer 1

The SysNative is a virtual directory that doesn't exist when running a 32-bit process.

Answer 2

This works interactively. I don't know about Intune though.

"Command path is $PSCommandPath"
if ($env:PROCESSOR_ARCHITEW6432 -eq "AMD64") {
    "Running as 32, launching 64 bit instance."
	$PsPath = "$env:SystemRoot\SysNative\WindowsPowerShell\v1.0\powershell.exe"
	$PsArgs = '-ExecutionPolicy', 'Bypass', '-File', $PSCommandPath
	Start-Process -FilePath $PsPath -ArgumentList $PsArgs
	Start-Sleep -seconds 10
	return
}	
"We are running x64."
if (([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator") -eq $false) {
	"We are not elevated."
	$PsPath = "$env:SystemRoot\System32\WindowsPowerShell\v1.0\powershell.exe"
	$PsArgs = '-ExecutionPolicy', 'Bypass', '-File', $PSCommandPath
	Start-Process -FilePath $PsPath -ArgumentList $PsArgs -Verb RunAs 
	Start-Sleep -seconds 10
	return
}	
"We are good to go."
start-sleep -seconds 10 
return