diff --git a/scripts/Windows/OS/Setup.ps1 b/scripts/Windows/OS/Setup.ps1
index 9cdd26fee..b9220218c 100644
--- a/scripts/Windows/OS/Setup.ps1
+++ b/scripts/Windows/OS/Setup.ps1
@@ -1,6 +1,9 @@
 $null = $env:WIN_COMPUTER_NAME;
 $null = $env:SETUP_SCRIPT_NAME;
 
+# Find `winiso` installation medium
+$drives = & wmic volume get "DriveLetter,Label";
+$drive = $($($drives | Select-String -Pattern "winiso") -split "\s+")[0];
 [xml]$unattendedConfig = $(Get-Content "$drive\Autounattend.template.xml");
 
 function Get-PassSettings {
@@ -12,9 +15,6 @@ function Get-PassSettings {
     return $unattendedConfig.SelectSingleNode("/unattend/settings[@pass='$passName']");
 }
 
-$drives = & wmic volume get "DriveLetter,Label";
-$drive = $($($drives | Select-String -Pattern "winiso") -split "\s+")[0];
-
 # Adjust unattended settings
 $specializeSettings = Get-PassSettings "specialize";
 $specializeSettings.SelectSingleNode("./component[@name='Microsoft-Windows-Shell-Setup']/ComputerName").InnerText = "$env:WIN_COMPUTER_NAME";