diff --git a/RemoveHKeyPrinters.ps1 b/RemoveHKeyPrinters.ps1
index d208531..a2639ab 100644
--- a/RemoveHKeyPrinters.ps1
+++ b/RemoveHKeyPrinters.ps1
@@ -1,3 +1,10 @@
+$flagFile = "C:\ProgramData\PrinterHKeyClean\v1.flag"
+
+if (Test-Path $flagFile) {
+    Write-Host "Script has already run. Exiting."
+    exit
+}
+
 $profileListKey = 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList'
 
 $sids = Get-ChildItem $profileListKey
@@ -48,4 +55,4 @@ net start spooler
 
 gpupdate /force
 
-New-Item -Path "C:\ProgramData\PrinterHKeyClean\v1.flag" -ItemType File -Force
+New-Item -Path $flagFile -ItemType File -Force