diff --git a/doc/manual/Makefile.am b/doc/manual/Makefile.am
index 55450c9a59..637d370c17 100644
--- a/doc/manual/Makefile.am
+++ b/doc/manual/Makefile.am
@@ -29,7 +29,7 @@ MANUAL_SRCS = manual.xml introduction.xml installation.xml \
  package-management.xml writing-nix-expressions.xml builtins.xml \
  build-farm.xml \
  $(man1_MANS:.1=.xml) $(man8_MANS:.8=.xml) \
- troubleshooting.xml bugs.xml opt-common.xml opt-common-syn.xml \
+ troubleshooting.xml bugs.xml opt-common.xml opt-common-syn.xml opt-inst-syn.xml \
  env-common.xml quick-start.xml nix-lang-ref.xml glossary.xml \
  conf-file.xml release-notes.xml \
  style.css images