diff --git a/wix/Moonlight/Moonlight.wixproj b/wix/Moonlight/Moonlight.wixproj
index 077d1f7a..fb1ff1df 100644
--- a/wix/Moonlight/Moonlight.wixproj
+++ b/wix/Moonlight/Moonlight.wixproj
@@ -16,7 +16,7 @@
     <SignOutput>true</SignOutput>
   </PropertyGroup>
   <Target Name="SignMsi">
-    <Exec Command='signtool.exe $(SIGNTOOL_PARAMS) %(SignMsi.FullPath)' />
+    <Exec Command='signtool.exe sign $(SIGNTOOL_PARAMS) %(SignMsi.FullPath)' />
   </Target>
   <ItemGroup>
     <PackageReference Include="WixToolset.Firewall.wixext" Version="7.0.0" />