diff --git a/mailnews/extensions/smime/public/MANIFEST_IDL b/mailnews/extensions/smime/public/MANIFEST_IDL
new file mode 100644
index 000000000000..1dc9ce0f478a
--- /dev/null
+++ b/mailnews/extensions/smime/public/MANIFEST_IDL
@@ -0,0 +1,5 @@
+#
+# This is a list of local files which get copied to the mozilla:dist:idl directory
+#
+
+nsIMsgSMIMEHeaderSink.idl