diff --git a/services/sync/modules/policies.js b/services/sync/modules/policies.js
index b972c6db42a4..3a84ea00626e 100644
--- a/services/sync/modules/policies.js
+++ b/services/sync/modules/policies.js
@@ -177,6 +177,7 @@ SyncScheduler.prototype = {
     if (Status.checkSetup() == STATUS_OK) {
       Svc.Obs.add("wake_notification", this);
       Svc.Obs.add("captive-portal-login-success", this);
+      Svc.Obs.add("sleep_notification", this);
       IdleService.addIdleObserver(this, Svc.Prefs.get("scheduler.idleTime"));
     }
   },
@@ -328,6 +329,7 @@ SyncScheduler.prototype = {
          IdleService.addIdleObserver(this, Svc.Prefs.get("scheduler.idleTime"));
          Svc.Obs.add("wake_notification", this);
          Svc.Obs.add("captive-portal-login-success", this);
+         Svc.Obs.add("sleep_notification", this);
          break;
       case "weave:service:start-over":
          this.setDefaults();
@@ -389,6 +391,9 @@ SyncScheduler.prototype = {
         CommonUtils.nextTick(() => {
           this.scheduleNextSync(3000);
         });
+      case "sleep_notification":
+        this._log.debug("Going to sleep, doing a quick sync.");
+        this.scheduleNextSync(0, ["tabs"], "sleep");
         break;
     }
   },
@@ -490,7 +495,7 @@ SyncScheduler.prototype = {
    *
    * Otherwise, reschedule a sync for later.
    */
-  syncIfMPUnlocked: function syncIfMPUnlocked() {
+  syncIfMPUnlocked(engines, why) {
     // No point if we got kicked out by the master password dialog.
     if (Status.login == MASTER_PASSWORD_LOCKED &&
         Utils.mpLocked()) {
@@ -506,13 +511,15 @@ SyncScheduler.prototype = {
       this._log.debug("Not initiating sync: app is shutting down");
       return;
     }
-    CommonUtils.nextTick(this.service.sync, this.service);
+    Services.tm.dispatchToMainThread(() => {
+      this.service.sync({engines, why});
+    });
   },
 
   /**
    * Set a timer for the next sync
    */
-  scheduleNextSync: function scheduleNextSync(interval) {
+  scheduleNextSync(interval, engines = null, why = null) {
     // If no interval was specified, use the current sync interval.
     if (interval == null) {
       interval = this.syncInterval;
@@ -543,12 +550,13 @@ SyncScheduler.prototype = {
     // Start the sync right away if we're already late.
     if (interval <= 0) {
       this._log.trace("Requested sync should happen right away.");
-      this.syncIfMPUnlocked();
+      this.syncIfMPUnlocked(engines, why);
       return;
     }
 
     this._log.debug("Next sync in " + interval + " ms.");
-    CommonUtils.namedTimer(this.syncIfMPUnlocked, interval, this, "syncTimer");
+    CommonUtils.namedTimer(() => { this.syncIfMPUnlocked(engines, why); },
+                           interval, this, "syncTimer");
 
     // Save the next sync time in-case sync is disabled (logout/offline/etc.)
     this.nextSync = Date.now() + interval;
diff --git a/services/sync/modules/service.js b/services/sync/modules/service.js
index f1d03a385ac2..a40a43017327 100644
--- a/services/sync/modules/service.js
+++ b/services/sync/modules/service.js
@@ -908,8 +908,8 @@ Sync11Service.prototype = {
 
   // Stuff we need to do after login, before we can really do
   // anything (e.g. key setup).
-  async _remoteSetup(infoResponse) {
-    if (!(await this._fetchServerConfiguration())) {
+  async _remoteSetup(infoResponse, fetchConfig = true) {
+    if (fetchConfig && !(await this._fetchServerConfiguration())) {
       return false;
     }
 
@@ -1112,7 +1112,7 @@ Sync11Service.prototype = {
       histogram.add(1);
 
       let synchronizer = new EngineSynchronizer(this);
-      await synchronizer.sync(engineNamesToSync); // Might throw!
+      await synchronizer.sync(engineNamesToSync, why); // Might throw!
 
       histogram = Services.telemetry.getHistogramById("WEAVE_COMPLETE_SUCCESS_COUNT");
       histogram.add(1);
diff --git a/services/sync/modules/stages/enginesync.js b/services/sync/modules/stages/enginesync.js
index 3ae7ee9e943a..36fe76ee3939 100644
--- a/services/sync/modules/stages/enginesync.js
+++ b/services/sync/modules/stages/enginesync.js
@@ -31,7 +31,8 @@ this.EngineSynchronizer = function EngineSynchronizer(service) {
 };
 
 EngineSynchronizer.prototype = {
-  async sync(engineNamesToSync) {
+  async sync(engineNamesToSync, why) {
+    let fastSync = why && why == "sleep";
     let startTime = Date.now();
 
     this.service.status.resetSync();
@@ -75,17 +76,19 @@ EngineSynchronizer.prototype = {
       engine.lastModified = info.obj[engine.name] || 0;
     }
 
-    if (!(await this.service._remoteSetup(info))) {
+    if (!(await this.service._remoteSetup(info, !fastSync))) {
       throw new Error("Aborting sync, remote setup failed");
     }
 
-    // Make sure we have an up-to-date list of clients before sending commands
-    this._log.debug("Refreshing client list.");
-    if (!(await this._syncEngine(this.service.clientsEngine))) {
-      // Clients is an engine like any other; it can fail with a 401,
-      // and we can elect to abort the sync.
-      this._log.warn("Client engine sync failed. Aborting.");
-      return;
+    if (!fastSync) {
+      // Make sure we have an up-to-date list of clients before sending commands
+      this._log.debug("Refreshing client list.");
+      if (!(await this._syncEngine(this.service.clientsEngine))) {
+        // Clients is an engine like any other; it can fail with a 401,
+        // and we can elect to abort the sync.
+        this._log.warn("Client engine sync failed. Aborting.");
+        return;
+      }
     }
 
     // We only honor the "hint" of what engines to Sync if this isn't
@@ -107,7 +110,7 @@ EngineSynchronizer.prototype = {
         break;
     }
 
-    if (this.service.clientsEngine.localCommands) {
+    if (!fastSync && this.service.clientsEngine.localCommands) {
       try {
         if (!(await this.service.clientsEngine.processIncomingCommands())) {
           this.service.status.sync = ABORT_SYNC_COMMAND;
@@ -179,7 +182,9 @@ EngineSynchronizer.prototype = {
         }
       }
 
-      await Doctor.consult(enginesToValidate);
+      if (!fastSync) {
+        await Doctor.consult(enginesToValidate);
+      }
 
       // If there were no sync engine failures
       if (this.service.status.service != SYNC_FAILED_PARTIAL) {