--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -4864,16 +4864,21 @@ MultiprocessBlockPolicy() {
 bool
 mozilla::BrowserTabsRemoteAutostart()
 {
   if (gBrowserTabsRemoteAutostartInitialized) {
     return gBrowserTabsRemoteAutostart;
   }
   gBrowserTabsRemoteAutostartInitialized = true;
 
+  // If we're in the content process, we are running E10S.
+  if (XRE_IsContentProcess()) {
+    gBrowserTabsRemoteAutostart = true;
+    return gBrowserTabsRemoteAutostart;
+  }
 
   bool optInPref = Preferences::GetBool("browser.tabs.remote.autostart", false);
   bool trialPref = Preferences::GetBool("browser.tabs.remote.autostart.2", false);
   bool prefEnabled = optInPref || trialPref;
   int status;
   if (optInPref) {
     status = kE10sEnabledByUser;
   } else if (trialPref) {