1 files changed, 1 insertions, 1 deletions

diff --git a/m/Makefile b/m/Makefile
index a92567c..272a6a9 100644
--- a/m/Makefile
+++ b/m/Makefile
@@ -20,7 +20,7 @@ McLachlan_BSSN.out: McLachlan_BSSN.m
 		./create-helper-thorn.sh $$thorn &&			   \
 		./copy-if-changed.sh $${thorn}_Helper ../$${thorn}_Helper; \
 	done
-	./copy-if-changed.sh ML_CCZ4 ../ML_CCZ4
+	[ -r ML_CCZ4 ] && ./copy-if-changed.sh ML_CCZ4 ../ML_CCZ4 \
 
 McLachlan_ADMConstraints.out: McLachlan_ADMConstraints.m
 	rm -rf ML_ADMConstraints*