diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index 06365ab..453db6f 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -1806,4 +1806,4 @@
 	rm -f $(all_final)
 .PHONY: clean neat
 
-.INTERMEDIATE: $(all_intermediate)
+.SECONDARY: $(all_intermediate)