diff --git a/src/components/structures/RoomView.js b/src/components/structures/RoomView.js
index 50fa18e075..f75393c6db 100644
--- a/src/components/structures/RoomView.js
+++ b/src/components/structures/RoomView.js
@@ -877,13 +877,12 @@ module.exports = React.createClass({
         // If the user is a ROU, allow them to transition to a PWLU
         if (cli && cli.isGuest()) {
             // Join this room once the user has registered and logged in
-            const signUrl = this.props.thirdPartyInvite ?
-                this.props.thirdPartyInvite.inviteSignUrl : undefined;
+            // (If we failed to peek, we may not have a valid room object.)
             dis.dispatch({
                 action: 'do_after_sync_prepared',
                 deferred_action: {
                     action: 'view_room',
-                    room_id: this.state.room.roomId,
+                    room_id: this.state.room ? this.state.room.roomId : this.state.roomId,
                 },
             });