diff --git a/src/quickfix.c b/src/quickfix.c
index a906114..f85fff5 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -4595,6 +4595,9 @@
 	    qf_winid = win->w_id;
 	}
 
+	// autocommands may cause trouble
+	incr_quickfix_busy();
+
 	if (old_last == NULL)
 	    // set curwin/curbuf to buf and save a few things
 	    aucmd_prepbuf(&aco, buf);
@@ -4616,6 +4619,9 @@
 	// when the added lines are not visible.
 	if ((win = qf_find_win(qi)) != NULL && old_line_count < win->w_botline)
 	    redraw_buf_later(buf, UPD_NOT_VALID);
+
+	// always called after incr_quickfix_busy()
+	decr_quickfix_busy();
     }
 }
 
diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index 2ee754b..bcaef5d 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -3455,6 +3455,21 @@
   endtry
 endfunc
 
+func Test_filetype_autocmd()
+  " this changes the location list while it is in use to fill a buffer
+  lexpr ''
+  lopen
+  augroup FT_loclist
+    au FileType * call setloclist(0, [], 'f')
+  augroup END
+  silent! lolder
+  lexpr ''
+
+  augroup FT_loclist
+    au! FileType
+  augroup END
+endfunc
+
 func Test_vimgrep_with_textlock()
   new
 
@@ -6372,4 +6387,5 @@
   call setqflist([], 'f')
 endfunc
 
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index b4756ca..7f72a2c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    805,
+/**/
     804,
 /**/
     803,