diff --git a/chalk/colorspaces/gray_u16/Makefile.am b/chalk/colorspaces/gray_u16/Makefile.am
index ed398249f..a168e5bad 100644
--- a/chalk/colorspaces/gray_u16/Makefile.am
+++ b/chalk/colorspaces/gray_u16/Makefile.am
@@ -27,3 +27,4 @@ chalk_gray_u16_plugin_la_METASOURCES = AUTO
 
 SUBDIRS = .
 
+.NOTPARALLEL:
diff --git a/kplato/Makefile.am b/kplato/Makefile.am
index 9b38e954b..96ea9294d 100644
--- a/kplato/Makefile.am
+++ b/kplato/Makefile.am
@@ -129,3 +129,5 @@ messages: rc.cpp
 kde_services_DATA = kplatopart.desktop
 
 include $(top_srcdir)/admin/Doxyfile.am
+
+.NOTPARALLEL: