diff --git a/user.js b/user.js
index d0d08f1..66c80e5 100644
--- a/user.js
+++ b/user.js
@@ -1446,6 +1446,9 @@ user_pref("security.csp.enable", true); // [DEFAULT: true]
 // Enforce a security delay on some confirmation dialogs such as install, open/save
 // https://www.squarefree.com/2004/07/01/race-conditions-in-security-dialogs/
 user_pref("security.dialog_enable_delay", 700);
+// -------------------------------------
+// Enable Site Isolation
+user_pref("fission.autostart", true);
 //
 // >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 // PERSISTENT STORAGE