diff --git a/src/option.c b/src/option.c
index 8e5021c..f3e4e20 100644
--- a/src/option.c
+++ b/src/option.c
@@ -9990,6 +9990,8 @@
     buf_T	*buf = (buf_T *)from;
 
     opt_idx = findoption(name);
+    if (opt_idx < 0)
+	return;
     p = &(options[opt_idx]);
 
     switch ((int)p->indir)