diff --git a/src/buffer.c b/src/buffer.c
index bd37830..5f8b1ad 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2353,6 +2353,7 @@
 #ifdef FEAT_CINDENT
     clear_string_option(&buf->b_p_cink);
     clear_string_option(&buf->b_p_cino);
+    clear_string_option(&buf->b_p_cinsd);
 #endif
 #if defined(FEAT_CINDENT) || defined(FEAT_SMARTINDENT)
     clear_string_option(&buf->b_p_cinw);