diff --git a/src/testdir/test_tabpage.vim b/src/testdir/test_tabpage.vim
index f1c41e9..7bdea0b 100644
--- a/src/testdir/test_tabpage.vim
+++ b/src/testdir/test_tabpage.vim
@@ -218,4 +218,18 @@
   bw!
 endfunction
 
+func Test_tabnext_on_buf_unload()
+  " This once caused a crash
+  new
+  tabedit
+  tabfirst
+  au BufUnload <buffer> tabnext
+  q
+
+  while tabpagenr('$') > 1
+    quit
+  endwhile
+endfunc
+
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index f5af115..5fd33ec 100644
--- a/src/version.c
+++ b/src/version.c
@@ -764,6 +764,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2309,
+/**/
     2308,
 /**/
     2307,
diff --git a/src/window.c b/src/window.c
index e62cd30..2f3ec8c 100644
--- a/src/window.c
+++ b/src/window.c
@@ -2379,7 +2379,7 @@
 #endif
 	close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, TRUE);
 #ifdef FEAT_AUTOCMD
-	if (win_valid(win))
+	if (win_valid_any_tab(win))
 	    win->w_closing = FALSE;
 #endif
 	/* Make sure curbuf is valid. It can become invalid if 'bufhidden' is
@@ -2399,9 +2399,18 @@
 	getout(0);
     }
 
-    /* Autocommands may have closed the window already, or closed the only
-     * other window or moved to another tab page. */
-    else if (!win_valid(win) || last_window() || curtab != prev_curtab
+    /* Autocommands may have moved to another tab page. */
+    if (curtab != prev_curtab && win_valid_any_tab(win)
+						      && win->w_buffer == NULL)
+    {
+	/* Need to close the window anyway, since the buffer is NULL. */
+	win_close_othertab(win, FALSE, prev_curtab);
+	return FAIL;
+    }
+
+    /* Autocommands may have closed the window already or closed the only
+     * other window. */
+    if (!win_valid(win) || last_window()
 	    || close_last_window_tabpage(win, free_buf, prev_curtab))
 	return FAIL;
 
@@ -2492,12 +2501,15 @@
     int		free_tp = FALSE;
 
 #ifdef FEAT_AUTOCMD
-    if (win->w_closing || win->w_buffer->b_closing)
+    /* Get here with win->w_buffer == NULL when win_close() detects the tab
+     * page changed. */
+    if (win->w_closing || (win->w_buffer != NULL && win->w_buffer->b_closing))
 	return; /* window is already being closed */
 #endif
 
-    /* Close the link to the buffer. */
-    close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, FALSE);
+    if (win->w_buffer != NULL)
+	/* Close the link to the buffer. */
+	close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, FALSE);
 
     /* Careful: Autocommands may have closed the tab page or made it the
      * current tab page.  */