--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -1104,19 +1104,17 @@ BrowserGlue.prototype = {
 
     // It's important that SafeBrowsing is initialized reasonably
     // early, so we use a maximum timeout for it.
     Services.tm.idleDispatchToMainThread(() => {
       SafeBrowsing.init();
     }, 5000);
 
     if (AppConstants.MOZ_CRASHREPORTER) {
-      Services.tm.idleDispatchToMainThread(() => {
-        UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
-      });
+      UnsubmittedCrashHandler.scheduleCheckForUnsubmittedCrashReports();
     }
 
     if (AppConstants.platform == "win") {
       Services.tm.idleDispatchToMainThread(() => {
         // For Windows 7, initialize the jump list module.
         const WINTASKBAR_CONTRACTID = "@mozilla.org/windows-taskbar;1";
         if (WINTASKBAR_CONTRACTID in Cc &&
             Cc[WINTASKBAR_CONTRACTID].getService(Ci.nsIWinTaskbar).available) {

--- a/browser/modules/ContentCrashHandlers.jsm
+++ b/browser/modules/ContentCrashHandlers.jsm
@@ -23,29 +23,36 @@ XPCOMUtils.defineLazyModuleGetter(this, 
 XPCOMUtils.defineLazyModuleGetter(this, "RemotePages",
   "resource://gre/modules/RemotePageManager.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "SessionStore",
   "resource:///modules/sessionstore/SessionStore.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "RecentWindow",
   "resource:///modules/RecentWindow.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "PluralForm",
   "resource://gre/modules/PluralForm.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "setTimeout",
+  "resource://gre/modules/Timer.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "clearTimeout",
+  "resource://gre/modules/Timer.jsm");
 
 XPCOMUtils.defineLazyGetter(this, "gNavigatorBundle", function() {
   const url = "chrome://browser/locale/browser.properties";
   return Services.strings.createBundle(url);
 });
 
 // We don't process crash reports older than 28 days, so don't bother
 // submitting them
 const PENDING_CRASH_REPORT_DAYS = 28;
 const DAY = 24 * 60 * 60 * 1000; // milliseconds
 const DAYS_TO_SUPPRESS = 30;
 const MAX_UNSEEN_CRASHED_CHILD_IDS = 20;
 
+// Time after which we will begin scanning for unsubmitted crash reports
+const CHECK_FOR_UNSUBMITTED_CRASH_REPORTS_DELAY_MS = 60 * 10000; // 10 minutes
+
 /**
  * BrowserWeakMap is exactly like a WeakMap, but expects <xul:browser>
  * objects only.
  *
  * Under the hood, BrowserWeakMap keys the map off of the <xul:browser>
  * permanentKey. If, however, the browser has never gotten a permanentKey,
  * it falls back to keying on the <xul:browser> element itself.
  */
@@ -580,16 +587,18 @@ this.UnsubmittedCrashHandler = {
   showingNotification: false,
   // suppressed is true if we've determined that we've shown
   // the notification too many times across too many days without
   // user interaction, so we're suppressing the notification for
   // some number of days. See the documentation for
   // shouldShowPendingSubmissionsNotification().
   suppressed: false,
 
+  _checkTimeout: null,
+
   init() {
     if (this.initialized) {
       return;
     }
 
     this.initialized = true;
 
     // UnsubmittedCrashHandler can be initialized but still be disabled.
@@ -616,16 +625,21 @@ this.UnsubmittedCrashHandler = {
 
   uninit() {
     if (!this.initialized) {
       return;
     }
 
     this.initialized = false;
 
+    if (this._checkTimeout) {
+      clearTimeout(this._checkTimeout);
+      this._checkTimeout = null;
+    }
+
     if (!this.enabled) {
       return;
     }
 
     if (this.suppressed) {
       this.suppressed = false;
       // No need to do any more clean-up, since we were suppressed.
       return;
@@ -643,16 +657,24 @@ this.UnsubmittedCrashHandler = {
     switch (topic) {
       case "profile-before-change": {
         this.uninit();
         break;
       }
     }
   },
 
+  scheduleCheckForUnsubmittedCrashReports() {
+    this._checkTimeout = setTimeout(() => {
+      Services.tm.idleDispatchToMainThread(() => {
+        this.checkForUnsubmittedCrashReports();
+      });
+    }, CHECK_FOR_UNSUBMITTED_CRASH_REPORTS_DELAY_MS);
+  },
+
   /**
    * Scans the profile directory for unsubmitted crash reports
    * within the past PENDING_CRASH_REPORT_DAYS days. If it
    * finds any, it will, if necessary, attempt to open a notification
    * bar to prompt the user to submit them.
    *
    * @returns Promise
    *          Resolves with the <xul:notification> after it tries to

--- a/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js
+++ b/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js
@@ -194,21 +194,27 @@ add_task(async function setup() {
   }
 
   let env = Cc["@mozilla.org/process/environment;1"]
               .getService(Components.interfaces.nsIEnvironment);
   let oldServerURL = env.get("MOZ_CRASHREPORTER_URL");
   env.set("MOZ_CRASHREPORTER_URL", SERVER_URL);
 
   // nsBrowserGlue starts up UnsubmittedCrashHandler automatically
-  // so at this point, it is initialized. It's possible that it
-  // was initialized, but is preffed off, so it's inert, so we
-  // shut it down, make sure it's preffed on, and then restart it.
-  // Note that making the component initialize even when it's
-  // disabled is an intentional choice, as this allows for easier
+  // on a timer, so at this point, it can be in one of several states:
+  //
+  // 1. The timer hasn't yet finished, and an automatic scan for crash
+  //    reports is pending.
+  // 2. The timer has already gone off and the scan has already completed.
+  // 3. The handler is disabled.
+  //
+  // To collapse all of these possibilities, we uninit the UnsubmittedCrashHandler
+  // to cancel the timer, make sure it's preffed on, and then restart it (which
+  // doesn't restart the timer). Note that making the component initialize
+  // even when it's disabled is an intentional choice, as this allows for easier
   // simulation of startup and shutdown.
   UnsubmittedCrashHandler.uninit();
 
   // While we're here, let's test that we don't show the notification
   // if we're disabled and something happens to check for unsubmitted
   // crash reports.
   await SpecialPowers.pushPrefEnv({
     set: [