diff --git a/contrib/msi/build-msi-gui.sh b/contrib/msi/build-msi-gui.sh
index 2fa85b4d..6d2c751a 100644
--- a/contrib/msi/build-msi-gui.sh
+++ b/contrib/msi/build-msi-gui.sh
@@ -309,7 +309,7 @@ cat > wix.xml << EOF
     <CustomAction Id="LaunchApplication" 
       Impersonate="yes" 
       FileKey="MeshUI"
-      ExeCommand="[MeshInstallFolder]ui\index.html" 
+      ExeCommand="\"[MeshInstallFolder]ui\index.html\"" 
       Return="asyncNoWait" />
 
     <!-- Step 3: Include the custom action -->