diff --git a/src/sliding-sync-sdk.ts b/src/sliding-sync-sdk.ts
index aab0ea45f..233c0c31d 100644
--- a/src/sliding-sync-sdk.ts
+++ b/src/sliding-sync-sdk.ts
@@ -293,13 +293,16 @@ export class SlidingSyncSdk {
         this.processRoomData(this.client, room, roomData);
     }
 
-    private onLifecycle(state: SlidingSyncState, resp: MSC3575SlidingSyncResponse, err?: Error): void {
+    private onLifecycle(state: SlidingSyncState, resp?: MSC3575SlidingSyncResponse, err?: Error): void {
         if (err) {
             logger.debug("onLifecycle", state, err);
         }
         switch (state) {
             case SlidingSyncState.Complete:
                 this.purgeNotifications();
+                if (!resp) {
+                    break;
+                }
                 // Element won't stop showing the initial loading spinner unless we fire SyncState.Prepared
                 if (!this.lastPos) {
                     this.updateSyncState(SyncState.Prepared, {
diff --git a/src/sliding-sync.ts b/src/sliding-sync.ts
index 712564e9d..da6419c96 100644
--- a/src/sliding-sync.ts
+++ b/src/sliding-sync.ts
@@ -323,7 +323,7 @@ export enum SlidingSyncEvent {
 export type SlidingSyncEventHandlerMap = {
     [SlidingSyncEvent.RoomData]: (roomId: string, roomData: MSC3575RoomData) => void;
     [SlidingSyncEvent.Lifecycle]: (
-        state: SlidingSyncState, resp: MSC3575SlidingSyncResponse | null, err: Error,
+        state: SlidingSyncState, resp: MSC3575SlidingSyncResponse | null, err: Error | null,
     ) => void;
     [SlidingSyncEvent.List]: (
         listIndex: number, joinedCount: number, roomIndexToRoomId: Record<number, string>,