diff --git a/src/components/views/elements/PersistentApp.js b/src/components/views/elements/PersistentApp.js
index d6931850be..391e7728f6 100644
--- a/src/components/views/elements/PersistentApp.js
+++ b/src/components/views/elements/PersistentApp.js
@@ -67,7 +67,7 @@ module.exports = createReactClass({
                     return ev.getStateKey() === ActiveWidgetStore.getPersistentWidgetId();
                 });
                 const app = WidgetUtils.makeAppConfig(
-                    appEvent.getStateKey(), appEvent.getContent(), appEvent.sender, persistentWidgetInRoomId,
+                    appEvent.getStateKey(), appEvent.getContent(), appEvent.getSender(), persistentWidgetInRoomId,
                 );
                 const capWhitelist = WidgetUtils.getCapWhitelistForAppTypeInRoomId(app.type, persistentWidgetInRoomId);
                 const AppTile = sdk.getComponent('elements.AppTile');
diff --git a/src/components/views/rooms/AppsDrawer.js b/src/components/views/rooms/AppsDrawer.js
index 2a0a7569fb..8e6319e315 100644
--- a/src/components/views/rooms/AppsDrawer.js
+++ b/src/components/views/rooms/AppsDrawer.js
@@ -107,7 +107,7 @@ module.exports = createReactClass({
             this.props.room.roomId, WidgetUtils.getRoomWidgets(this.props.room),
         );
         return widgets.map((ev) => {
-            return WidgetUtils.makeAppConfig(ev.getStateKey(), ev.getContent(), ev.sender);
+            return WidgetUtils.makeAppConfig(ev.getStateKey(), ev.getContent(), ev.getSender());
         });
     },
 
diff --git a/src/utils/WidgetUtils.js b/src/utils/WidgetUtils.js
index 36907da5ab..eb26ff1484 100644
--- a/src/utils/WidgetUtils.js
+++ b/src/utils/WidgetUtils.js
@@ -400,7 +400,7 @@ export default class WidgetUtils {
         return client.setAccountData('m.widgets', userWidgets);
     }
 
-    static makeAppConfig(appId, app, sender, roomId) {
+    static makeAppConfig(appId, app, senderUserId, roomId) {
         const myUserId = MatrixClientPeg.get().credentials.userId;
         const user = MatrixClientPeg.get().getUser(myUserId);
         const params = {
@@ -413,6 +413,11 @@ export default class WidgetUtils {
             '$theme': SettingsStore.getValue("theme"),
         };
 
+        if (!senderUserId) {
+            throw new Error("Widgets must be created by someone - provide a senderUserId");
+        }
+        app.creatorUserId = senderUserId;
+
         app.id = appId;
         app.name = app.name || app.type;
 
@@ -425,7 +430,6 @@ export default class WidgetUtils {
         }
 
         app.url = encodeUri(app.url, params);
-        app.creatorUserId = (sender && sender.userId) ? sender.userId : null;
 
         return app;
     }