After bug 1198459, enabling preference browser.tabs.remote.force-enable successfully forces e10s, but the console still says e10s is disabled: > E10s has been blocked from running because: An accessibility tool is or was active. See bug 1198459. From bug 1198459 comment 64 this is expected, but perhaps a follow-up message would be nice, as that message is misleading since e10s isn't actually blocked. Something like "E10s is running anyway, because you have force-enabled it in about:config."