diff --git a/src/nsterm.m b/src/nsterm.m
index 03754e5ae5..c1d1d41117 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1644,6 +1644,7 @@ Hide the window (X11 semantics)
   [view release];
 
   xfree (f->output_data.ns);
+  f->output_data.ns = NULL;
 
   unblock_input ();
 }