diff --git a/autoload/ale/util.vim b/autoload/ale/util.vim
index d7b6904c..267b0587 100644
--- a/autoload/ale/util.vim
+++ b/autoload/ale/util.vim
@@ -268,9 +268,8 @@ endfunction
 " See :help sandbox
 function! ale#util#InSandbox() abort
     try
-        function! s:SandboxCheck() abort
-        endfunction
-    catch /^Vim\%((\a\+)\)\=:E48/
+        let &equalprg=&equalprg
+    catch /E48/
         " E48 is the sandbox error.
         return 1
     endtry