diff --git a/toolkit/components/places/PlacesDBUtils.jsm b/toolkit/components/places/PlacesDBUtils.jsm
index b8f4e1affc1..d759f226460 100644
--- a/toolkit/components/places/PlacesDBUtils.jsm
+++ b/toolkit/components/places/PlacesDBUtils.jsm
@@ -67,7 +67,6 @@ this.PlacesDBUtils = {
       }
 
       // Notify observers that maintenance finished.
-      Services.prefs.setIntPref("places.database.lastMaintenance", parseInt(Date.now() / 1000));
       Services.obs.notifyObservers(null, FINISHED_MAINTENANCE_TOPIC, null);
     }
   },
@@ -94,7 +93,12 @@ this.PlacesDBUtils = {
     , this._refreshUI
     ]);
     tasks._telemetryStart = Date.now();
-    tasks.callback = aCallback;
+    tasks.callback = function() {
+      Services.prefs.setIntPref("places.database.lastMaintenance",
+                                parseInt(Date.now() / 1000));
+      if (aCallback)
+        aCallback();
+    }
     tasks.scope = aScope;
     this._executeTasks(tasks);
   },
diff --git a/toolkit/components/places/tests/unit/test_preventive_maintenance.js b/toolkit/components/places/tests/unit/test_preventive_maintenance.js
index 1f4a616432f..bc87e6bad98 100644
--- a/toolkit/components/places/tests/unit/test_preventive_maintenance.js
+++ b/toolkit/components/places/tests/unit/test_preventive_maintenance.js
@@ -1279,14 +1279,17 @@ add_task(function test_preventive_maintenance()
   stmt.finalize();
   do_check_true(defaultBookmarksMaxId > 0);
 
-  for ([, test] in Iterator(tests)) {
+  for (let [, test] in Iterator(tests)) {
     dump("\nExecuting test: " + test.name + "\n" + "*** " + test.desc + "\n");
     yield test.setup();
 
     let promiseMaintenanceFinished =
         promiseTopicObserved(FINISHED_MAINTENANCE_NOTIFICATION_TOPIC);
-    PlacesDBUtils.maintenanceOnIdle();
+    Services.prefs.clearUserPref("places.database.lastMaintenance");
+    let callbackInvoked = false;
+    PlacesDBUtils.maintenanceOnIdle(() => callbackInvoked = true);
     yield promiseMaintenanceFinished;
+    do_check_true(callbackInvoked);
 
     // Check the lastMaintenance time has been saved.
     do_check_neq(Services.prefs.getIntPref("places.database.lastMaintenance"), null);
diff --git a/toolkit/components/places/tests/unit/test_telemetry.js b/toolkit/components/places/tests/unit/test_telemetry.js
index 7c6ddae2e7b..2853c9e47ff 100644
--- a/toolkit/components/places/tests/unit/test_telemetry.js
+++ b/toolkit/components/places/tests/unit/test_telemetry.js
@@ -126,6 +126,7 @@ add_task(function test_execute()
 });
 
 add_test(function test_healthreport_callback() {
+  Services.prefs.clearUserPref("places.database.lastMaintenance");
   PlacesDBUtils.telemetry(null, function onResult(data) {
     do_check_neq(data, null);
 
@@ -133,6 +134,7 @@ add_test(function test_healthreport_callback() {
     do_check_eq(data.PLACES_PAGES_COUNT, 1);
     do_check_eq(data.PLACES_BOOKMARKS_COUNT, 1);
 
+    do_check_true(!Services.prefs.prefHasUserValue("places.database.lastMaintenance"));
     run_next_test();
   });
 });