diff --git a/js/misc/util.js b/js/misc/util.js
index 670fbff769..9dff70a646 100644
--- a/js/misc/util.js
+++ b/js/misc/util.js
@@ -369,12 +369,12 @@ const _IGNORED_PHRASES = [
 ];
 
 function fixupPCIDescription(desc) {
-    desc = desc.replace(/[_,]/, ' ');
+    desc = desc.replace(/[_,]/g, ' ');
 
     /* Remove any parenthesized info longer than 2 chars (which
        may be disambiguating numbers if there are multiple identical
        cards present) */
-    desc = desc.replace(/\([\s\S][^\(\)]{2,}\)/, '');
+    desc = desc.replace(/\([\s\S][^\(\)]{2,}\)/g, '');
 
     /* Attempt to shorten ID by ignoring certain phrases */
     for (let i = 0; i < _IGNORED_PHRASES.length; i++) {
diff --git a/js/ui/cinnamonDBus.js b/js/ui/cinnamonDBus.js
index 086e3ef837..21e9bf394f 100644
--- a/js/ui/cinnamonDBus.js
+++ b/js/ui/cinnamonDBus.js
@@ -374,6 +374,10 @@ var CinnamonDBus = class {
 
     activateCallback(callback, uuid, instance_id) {
         let obj = this._getXletObject(uuid, instance_id);
+        if (!obj) {
+            global.logWarning(`[CinnamonDBus] activateCallback: xlet not found (uuid=${uuid}, instance_id=${instance_id})`);
+            return;
+        }
         let cb = obj[callback].bind(obj);
         cb();
     }
@@ -386,6 +390,13 @@ var CinnamonDBus = class {
             );
             return;
         }
+        if (!Main.settingsManager.uuids[uuid][instance_id]) {
+            global.logWarning(
+                `[CinnamonDBus] [${uuid}] Unable to find instance '${instance_id}' from SettingsManager - ` +
+                'this is likely due to configuring settings from a removed xlet instance.'
+            );
+            return;
+        }
         Main.settingsManager.uuids[uuid][instance_id].remoteUpdate(key, payload);
     }
 
@@ -549,7 +560,6 @@ var CinnamonDBus = class {
 
         for (let idx in sources) {
             const source = sources[idx];
-            // global.log(source.preferences);
             ret.push([
                 source.type,
                 source.id,
diff --git a/js/ui/keyboardManager.js b/js/ui/keyboardManager.js
index bf23d4b58e..ff9f94f2bc 100644
--- a/js/ui/keyboardManager.js
+++ b/js/ui/keyboardManager.js
@@ -12,11 +12,11 @@ const PopupMenu = imports.ui.popupMenu;
 const Cairo = imports.cairo;
 const Util = imports.misc.util;
 
-DESKTOP_INPUT_SOURCES_SCHEMA = 'org.cinnamon.desktop.input-sources';
-KEY_INPUT_SOURCES = 'sources';
-KEY_KEYBOARD_OPTIONS = 'xkb-options';
-KEY_PER_WINDOW = 'per-window';
-KEY_SOURCE_LAYOUTS = 'source-layouts';
+var DESKTOP_INPUT_SOURCES_SCHEMA = 'org.cinnamon.desktop.input-sources';
+var KEY_INPUT_SOURCES = 'sources';
+var KEY_KEYBOARD_OPTIONS = 'xkb-options';
+var KEY_PER_WINDOW = 'per-window';
+var KEY_SOURCE_LAYOUTS = 'source-layouts';
 
 var INPUT_SOURCE_TYPE_XKB = 'xkb';
 var INPUT_SOURCE_TYPE_IBUS = 'ibus';
diff --git a/js/ui/notificationDaemon.js b/js/ui/notificationDaemon.js
index 7c01633a5c..2ba1b3d29b 100644
--- a/js/ui/notificationDaemon.js
+++ b/js/ui/notificationDaemon.js
@@ -173,6 +173,9 @@ NotificationDaemon.prototype = {
                 case Urgency.CRITICAL:
                     stockIcon = 'xsi-dialog-error-symbolic';
                     break;
+                default:
+                    stockIcon = 'xsi-dialog-information-symbolic';
+                    break;
             }
             return new St.Icon({ icon_name: stockIcon,
                                  icon_type: St.IconType.SYMBOLIC,
@@ -265,7 +268,13 @@ NotificationDaemon.prototype = {
         let ndata = this._expireNotifications[0];
 
         if (ndata) {
-            ndata.notification.destroy(MessageTray.NotificationDestroyedReason.EXPIRED);
+            if (ndata.notification) {
+                ndata.notification.destroy(MessageTray.NotificationDestroyedReason.EXPIRED);
+            } else {
+                // notification object not yet created (async PID lookup still pending)
+                this._expireNotifications.shift();
+                this._restartExpire();
+            }
         }
 
         this._expireTimer = 0;
diff --git a/js/ui/windowManager.js b/js/ui/windowManager.js
index 5075b19965..6f5fd57db6 100644
--- a/js/ui/windowManager.js
+++ b/js/ui/windowManager.js
@@ -100,9 +100,9 @@ class DisplayChangeDialog extends ModalDialog.ModalDialog {
     }
 
     _formatCountDown() {
-        let fmt = ngettext("Reverting to previous display settings in %d second.",
-                           "Reverting to previous display settings in %d seconds.");
-        return fmt.format(this._countDown);
+        return ngettext("Reverting to previous display settings in %d second.",
+                        "Reverting to previous display settings in %d seconds.",
+                        this._countDown).format(this._countDown);
     }
 
     _tick() {