diff --git a/ftplugin/qf.vim b/ftplugin/qf.vim
index 7da45a4c..27564fa7 100644
--- a/ftplugin/qf.vim
+++ b/ftplugin/qf.vim
@@ -1,4 +1,4 @@
-if g:ack_autofold_results
+if exists("g:ack_autofold_results") && g:ack_autofold_results
   setlocal foldlevel=0
   setlocal foldmethod=expr
   setlocal foldexpr=matchstr(getline(v:lnum),'^[^\|]\\+')==#matchstr(getline(v:lnum+1),'^[^\|]\\+')?1:'<1'