--- a/mobile/android/components/SessionStore.js
+++ b/mobile/android/components/SessionStore.js
@@ -143,16 +143,17 @@ SessionStore.prototype = {
     this._maxTabsUndo = Services.prefs.getIntPref(PREFS_MAX_TABS_UNDO);
     if (this._maxTabsUndo == 0) {
       this._forgetClosedTabs();
     }
   },
 
   _clearDisk: function ss_clearDisk() {
     this._sessionDataIsGood = false;
+    this._lastBackupTime = 0;
 
     if (this._loadState > STATE_QUITTING) {
       OS.File.remove(this._sessionFile.path);
       OS.File.remove(this._sessionFileBackup.path);
       OS.File.remove(this._sessionFilePrevious.path);
       OS.File.remove(this._sessionFileTemp.path);
     } else { // We're shutting down and must delete synchronously
       if (this._sessionFile.exists()) { this._sessionFile.remove(false); }
@@ -592,16 +593,23 @@ SessionStore.prototype = {
 
     // Record the current scroll position and zoom level.
     aBrowser.addEventListener("scroll", this, true);
     aBrowser.addEventListener("resize", this, true);
 
     log("onTabAdd() ran for tab " + aWindow.BrowserApp.getTabForBrowser(aBrowser).id +
         ", aNoNotification = " + aNoNotification);
     if (!aNoNotification) {
+      if (this._loadState == STATE_QUITTING) {
+        // A tab arrived just as were starting to shut down. Since we haven't yet received
+        // application-quit, we refresh the window data one more time before the window closes.
+        this._forEachBrowserWindow((aWindow) => {
+          this._collectWindowData(aWindow);
+        });
+      }
       this.saveStateDelayed();
     }
     this._updateCrashReportURL(aWindow);
   },
 
   onTabRemove: function ss_onTabRemove(aWindow, aBrowser, aNoNotification) {
     // Cleanup event listeners
     aBrowser.removeEventListener("DOMTitleChanged", this, true);