[Solved] You wrote this PowerShell script to run only on Windows: if ($IsWindows) { Write-Output 'Windows detected' } else { Write-Output 'Not Windows' } But it always outputs 'Not Windows' even on Windows.... | PowerShell

PowerShell - Cross-Platform PowerShell

You wrote this PowerShell script to run only on Windows:

if ($IsWindows) {
  Write-Output 'Windows detected'
} else {
  Write-Output 'Not Windows'
}

But it always outputs 'Not Windows' even on Windows. What is the likely problem?

AYou ran the script in PowerShell Core on Windows but $IsWindows is true only in Windows PowerShell

BYou ran the script in PowerShell Core on Windows where $IsWindows is false

CYou ran the script in Windows PowerShell 5.1 on Windows where $IsWindows does not exist

DYou used $IsWindows without the $ sign

Step-by-Step Solution

Solution:

Step 1: Understand $IsWindows availability
The $IsWindows automatic variable exists only in PowerShell Core 6.0+ and is true on Windows.
Step 2: Identify the likely problem
In legacy Windows PowerShell 5.1, $IsWindows does not exist ($null/false), so the if condition fails even on Windows.
Final Answer:
You ran the script in Windows PowerShell 5.1 on Windows where $IsWindows does not exist -> Option C
Quick Check:
$IsWindows unavailable in PS 5.1 [OK]

Quick Trick: Verify your PowerShell edition (powershell.exe vs pwsh.exe) [OK]

Common Mistakes:

Master "Cross-Platform PowerShell" in PowerShell

9 interactive learning modes - each teaches the same concept differently

More PowerShell Quizzes

You wrote this PowerShell script to run only on Windows: