diff --git a/src/vector/indexeddb-worker.ts b/src/vector/indexeddb-worker.ts
index 85070079de..e196cdfb35 100644
--- a/src/vector/indexeddb-worker.ts
+++ b/src/vector/indexeddb-worker.ts
@@ -14,8 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { IndexedDBStoreWorker } from 'matrix-js-sdk/src/indexeddb-worker.js';
+import { IndexedDBStoreWorker } from 'matrix-js-sdk/src/indexeddb-worker';
 
-const remoteWorker = new IndexedDBStoreWorker(postMessage);
+const remoteWorker = new IndexedDBStoreWorker(postMessage as InstanceType<typeof Worker>["postMessage"]);
 
 global.onmessage = remoteWorker.onMessage;