diff --git a/src/enc/Makefile.am b/src/enc/Makefile.am
index 02d950dc..15d9b22e 100644
--- a/src/enc/Makefile.am
+++ b/src/enc/Makefile.am
@@ -23,7 +23,6 @@ libwebpencodeinclude_HEADERS += ../webp/encode.h
 libwebpencodeinclude_HEADERS += ../webp/types.h
 noinst_HEADERS =
 noinst_HEADERS += ../webp/format_constants.h
-noinst_HEADERS += ../webp/mux.h
 
 libwebpencode_la_LDFLAGS = -lm
 libwebpencode_la_CPPFLAGS = $(USE_EXPERIMENTAL_CODE)