diff --git a/src/scriptfile.c b/src/scriptfile.c
index 56186ff..0d39f38 100644
--- a/src/scriptfile.c
+++ b/src/scriptfile.c
@@ -2156,7 +2156,11 @@
 
     if (p == NULL)
 	return NULL;
+#ifdef CASE_INSENSITIVE_FILENAME
     prefix = strlow_save(p);
+#else
+    prefix = vim_strsave(p);
+#endif
     if (prefix == NULL)
 	return NULL;