diff --git a/scripts/Windows/Config/Firefox/Install.ps1 b/scripts/Windows/Config/Firefox/Install.ps1
index c4a179836..19ff9a467 100644
--- a/scripts/Windows/Config/Firefox/Install.ps1
+++ b/scripts/Windows/Config/Firefox/Install.ps1
@@ -21,6 +21,7 @@ $reader.Dispose();
 $extensions = @(
     ".htm",
     ".html",
+    ".shtml",
     ".svg",
     ".xht",
     ".xhtml"