diff --git a/src/buffer.c b/src/buffer.c
index 7a6dbc5917..5a9f8a786c 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -5702,8 +5702,8 @@ buf_delete_signs(buf)
     signlist_T	*next;
 
     /* When deleting the last sign need to redraw the windows to remove the
-     * sign column. */
-    if (buf->b_signlist != NULL)
+     * sign column. Not when curwin is NULL (this means we're exiting). */
+    if (buf->b_signlist != NULL && curwin != NULL)
     {
 	redraw_buf_later(buf, NOT_VALID);
 	changed_cline_bef_curs();
diff --git a/src/version.c b/src/version.c
index 407541af05..cd1ce94c5b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    369,
 /**/
     368,
 /**/
diff --git a/src/window.c b/src/window.c
index cbf0ff86b4..de85739a0e 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2489,6 +2489,10 @@ win_free_all()
 
     while (firstwin != NULL)
 	(void)win_free_mem(firstwin, &dummy, NULL);
+
+    /* No window should be used after this. Set curwin to NULL to crash
+     * instead of using freed memory. */
+    curwin = NULL;
 }
 #endif