diff --git a/src/channel.c b/src/channel.c
index 7edca1a..aed234c 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -5947,6 +5947,11 @@
 	if (win32_build_cmd(l, &ga) == FAIL)
 	    goto theend;
 	cmd = ga.ga_data;
+	if (cmd == NULL)
+	{
+	    emsg(_(e_invarg));
+	    goto theend;
+	}
 #endif
     }