diff --git a/src/buffer.c b/src/buffer.c
index 7a6dbc5..5a9f8a7 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -5702,8 +5702,8 @@
     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 407541a..cd1ce94 100644
--- a/src/version.c
+++ b/src/version.c
@@ -735,6 +735,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    369,
+/**/
     368,
 /**/
     367,
diff --git a/src/window.c b/src/window.c
index cbf0ff8..de85739 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2489,6 +2489,10 @@
 
     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