diff --git a/toolkit/mozapps/extensions/test/xpcshell/head_addons.js b/toolkit/mozapps/extensions/test/xpcshell/head_addons.js
index 64c0c7b36cc..4b0f68459a8 100644
--- a/toolkit/mozapps/extensions/test/xpcshell/head_addons.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/head_addons.js
@@ -28,8 +28,6 @@ Components.utils.import("resource://gre/modules/Task.jsm");
 Components.utils.import("resource://gre/modules/osfile.jsm");
 Components.utils.import("resource://gre/modules/AsyncShutdown.jsm");
 
-Services.prefs.setBoolPref("toolkit.osfile.log", true);
-
 // We need some internal bits of AddonManager
 let AMscope = Components.utils.import("resource://gre/modules/AddonManager.jsm");
 let AddonManager = AMscope.AddonManager;