diff --git a/Updater/Update-Service.ps1 b/Updater/Update-Service.ps1
index e4d09463854fa062e04edd8841cffe2ab3c9af0b..5a70ec871ad19e45812732d7fe285b19bc654e0d 100644
--- a/Updater/Update-Service.ps1
+++ b/Updater/Update-Service.ps1
@@ -34,7 +34,8 @@ function ServiceIsBusy {
     $StatusXml = "$($InstallationPath)\status.xml"
     try {
         [xml]$XML = Get-Content $StatusXml -ErrorAction Stop
-        if ($XML.ServiceStatus.TransferInProgress) {
+        # careful, we need a string comparison here:
+        if ($XML.ServiceStatus.TransferInProgress -eq "true") {
             Return $True
         } else {
             Log-Debug "Service is idle, shutdown possible."