diff --git a/src/MatrixClientPeg.js b/src/MatrixClientPeg.js
index 9865044717..f02c751a2c 100644
--- a/src/MatrixClientPeg.js
+++ b/src/MatrixClientPeg.js
@@ -18,6 +18,8 @@ limitations under the License.
 
 'use strict';
 
+import Matrix from 'matrix-js-sdk';
+
 import utils from 'matrix-js-sdk/lib/utils';
 import EventTimeline from 'matrix-js-sdk/lib/models/event-timeline';
 import EventTimelineSet from 'matrix-js-sdk/lib/models/event-timeline-set';
@@ -51,6 +53,9 @@ class MatrixClientPeg {
         this.opts = {
             initialSyncLimit: 20,
         };
+        // the credentials used to init the current client object.
+        // used if we tear it down & recreate it with a different store
+        this._currentClientCreds = null;
     }
 
     /**
@@ -79,10 +84,30 @@ class MatrixClientPeg {
      * Home Server / Identity Server URLs and active credentials
      */
     replaceUsingCreds(creds: MatrixClientCreds) {
+        this._currentClientCreds = creds;
         this._createClient(creds);
     }
 
     async start() {
+        for (const dbType of ['indexeddb', 'memory']) {
+            try {
+                const promise = this.matrixClient.store.startup();
+                console.log("MatrixClientPeg: waiting for MatrixClient store to initialise");
+                await promise;
+                break;
+            } catch (err) {
+                if (dbType === 'indexeddb') {
+                    console.error('Error starting matrixclient store - falling back to memory store', err);
+                    this.matrixClient.store = new Matrix.MatrixInMemoryStore({
+                      localStorage: global.localStorage,
+                    });
+                } else {
+                    console.error('Failed to start memory store!', err);
+                    throw err;
+                }
+            }
+        }
+
         // try to initialise e2e on the new client
         try {
             // check that we have a version of the js-sdk which includes initCrypto
@@ -103,18 +128,6 @@ class MatrixClientPeg {
             opts.lazyLoadMembers = true;
         }
 
-        try {
-            const promise = this.matrixClient.store.startup();
-            console.log(`MatrixClientPeg: waiting for MatrixClient store to initialise`);
-            await promise;
-        } catch (err) {
-            // log any errors when starting up the database (if one exists)
-            console.error('Error starting matrixclient store', err);
-        }
-
-        // regardless of errors, start the client. If we did error out, we'll
-        // just end up doing a full initial /sync.
-
         // Connect the matrix client to the dispatcher
         MatrixActionCreators.start(this.matrixClient);
 
@@ -147,7 +160,7 @@ class MatrixClientPeg {
         return matches[1];
     }
 
-    _createClient(creds: MatrixClientCreds) {
+    _createClient(creds: MatrixClientCreds, useIndexedDb) {
         const opts = {
             baseUrl: creds.homeserverUrl,
             idBaseUrl: creds.identityServerUrl,
@@ -158,7 +171,7 @@ class MatrixClientPeg {
             forceTURN: SettingsStore.getValue('webRtcForceTURN', false),
         };
 
-        this.matrixClient = createMatrixClient(opts, this.indexedDbWorkerScript);
+        this.matrixClient = createMatrixClient(opts, useIndexedDb);
 
         // we're going to add eventlisteners for each matrix event tile, so the
         // potential number of event listeners is quite high.
diff --git a/src/utils/createMatrixClient.js b/src/utils/createMatrixClient.js
index 54312695b6..2acd1fae28 100644
--- a/src/utils/createMatrixClient.js
+++ b/src/utils/createMatrixClient.js
@@ -32,13 +32,18 @@ try {
  * @param {Object} opts  options to pass to Matrix.createClient. This will be
  *    extended with `sessionStore` and `store` members.
  *
+ * @param {bool} useIndexedDb True to attempt to use indexeddb, or false to force
+ *     use of the memory store. Default: true.
+ *
  * @property {string} indexedDbWorkerScript  Optional URL for a web worker script
  *    for IndexedDB store operations. By default, indexeddb ops are done on
  *    the main thread.
  *
  * @returns {MatrixClient} the newly-created MatrixClient
  */
-export default function createMatrixClient(opts) {
+export default function createMatrixClient(opts, useIndexedDb) {
+    if (useIndexedDb === undefined) useIndexedDb = true;
+
     const storeOpts = {
         useAuthorizationHeader: true,
     };
@@ -47,7 +52,7 @@ export default function createMatrixClient(opts) {
         storeOpts.sessionStore = new Matrix.WebStorageSessionStore(localStorage);
     }
 
-    if (indexedDB && localStorage) {
+    if (indexedDB && localStorage && useIndexedDb) {
         storeOpts.store = new Matrix.IndexedDBStore({
             indexedDB: indexedDB,
             dbName: "riot-web-sync",