diff --git a/src/client/initMatrix.ts b/src/client/initMatrix.ts
index 6ac3e4f2..b64fa883 100644
--- a/src/client/initMatrix.ts
+++ b/src/client/initMatrix.ts
@@ -21,18 +21,21 @@ export const initClient = async (session: Session): Promise<MatrixClient> => {
     dbName: 'web-sync-store',
   });
 
+  const legacyCryptoStore = new IndexedDBCryptoStore(global.indexedDB, 'crypto-store');
+
   const mx = createClient({
     baseUrl: session.baseUrl,
     accessToken: session.accessToken,
     userId: session.userId,
     store: indexedDBStore,
-    cryptoStore: new IndexedDBCryptoStore(global.indexedDB, 'crypto-store'),
+    cryptoStore: legacyCryptoStore,
     deviceId: session.deviceId,
     timelineSupport: true,
     cryptoCallbacks: cryptoCallbacks as any,
     verificationMethods: ['m.sas.v1'],
   });
 
+  await indexedDBStore.startup();
   await mx.initRustCrypto();
 
   mx.setGlobalErrorOnUnknownDevices(false);