--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -8229,21 +8229,16 @@
   },
   "LOOP_ROOM_SESSION_WITHCHAT": {
     "alert_emails": ["firefox-dev@mozilla.org", "mdeboer@mozilla.com"],
     "expires_in_version": "47",
     "kind": "count",
     "releaseChannelCollection": "opt-out",
     "description": "Number of sessions where at least one chat message was exchanged"
   },
-  "E10S_AUTOSTART": {
-    "expires_in_version": "never",
-    "kind": "boolean",
-    "description": "Whether a session is set to autostart e10s windows"
-  },
   "E10S_AUTOSTART_STATUS": {
     "expires_in_version": "never",
     "kind": "enumerated",
     "n_values": 6,
     "description": "Why e10s is enabled or disabled (0=ENABLED_BY_USER, 1=ENABLED_BY_DEFAULT, 2=DISABLED_BY_USER, 3=DISABLED_IN_SAFE_MODE, 4=DISABLED_FOR_ACCESSIBILITY, 5=DISABLED_FOR_MAC_GFX)"
   },
   "E10S_WINDOW": {
     "expires_in_version": "never",

--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -4777,17 +4777,16 @@ mozilla::BrowserTabsRemoteAutostart()
 
   // Uber override pref for manual testing purposes
   if (Preferences::GetBool(kForceEnableE10sPref, false)) {
     gBrowserTabsRemoteAutostart = true;
     prefEnabled = true;
     status = kE10sEnabledByUser;
   }
 
-  mozilla::Telemetry::Accumulate(mozilla::Telemetry::E10S_AUTOSTART, gBrowserTabsRemoteAutostart);
   mozilla::Telemetry::Accumulate(mozilla::Telemetry::E10S_AUTOSTART_STATUS, status);
   if (Preferences::GetBool("browser.enabledE10SFromPrompt", false)) {
     mozilla::Telemetry::Accumulate(mozilla::Telemetry::E10S_STILL_ACCEPTED_FROM_PROMPT,
                                     gBrowserTabsRemoteAutostart);
   }
   if (prefEnabled) {
     mozilla::Telemetry::Accumulate(mozilla::Telemetry::E10S_BLOCKED_FROM_RUNNING,
                                     !gBrowserTabsRemoteAutostart);