diff --git a/src/MatrixClientPeg.js b/src/MatrixClientPeg.js
index 04b3b47e43..9a77901d2e 100644
--- a/src/MatrixClientPeg.js
+++ b/src/MatrixClientPeg.js
@@ -23,10 +23,12 @@ 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';
+import sdk from './index';
 import createMatrixClient from './utils/createMatrixClient';
 import SettingsStore from './settings/SettingsStore';
 import MatrixActionCreators from './actions/MatrixActionCreators';
 import {phasedRollOutExpiredForUser} from "./PhasedRollOut";
+import Modal from './Modal';
 
 interface MatrixClientCreds {
     homeserverUrl: string,
@@ -116,6 +118,14 @@ class MatrixClientPeg {
                 await this.matrixClient.initCrypto();
             }
         } catch (e) {
+            if (e.name === 'InvalidCryptoStoreError') {
+                // The js-sdk found a crypto DB too new for it to use
+                const CryptoStoreTooNewDialog =
+                    sdk.getComponent("views.dialogs.CryptoStoreTooNewDialog");
+                Modal.createDialog(CryptoStoreTooNewDialog, {
+                    host: window.location.host,
+                });
+            }
             // this can happen for a number of reasons, the most likely being
             // that the olm library was missing. It's not fatal.
             console.warn("Unable to initialise e2e: " + e);
diff --git a/src/components/views/dialogs/CryptoStoreTooNewDialog.js b/src/components/views/dialogs/CryptoStoreTooNewDialog.js
new file mode 100644
index 0000000000..0146420f46
--- /dev/null
+++ b/src/components/views/dialogs/CryptoStoreTooNewDialog.js
@@ -0,0 +1,71 @@
+/*
+Copyright 2018 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+import sdk from '../../../index';
+import dis from '../../../dispatcher';
+import { _t } from '../../../languageHandler';
+import Modal from '../../../Modal';
+
+export default (props) => {
+    const _onLogoutClicked = () => {
+        const QuestionDialog = sdk.getComponent("dialogs.QuestionDialog");
+        Modal.createTrackedDialog('Logout e2e db too new', '', QuestionDialog, {
+            title: _t("Sign out"),
+            description: _t(
+                "To avoid losing your chat history, you must export your room keys " +
+                "before logging out. You will need to go back to the newer version of " +
+                "Riot to do this",
+            ),
+            button: _t("Sign out"),
+            focus: false,
+            onFinished: (doLogout) => {
+                if (doLogout) {
+                    dis.dispatch({action: 'logout'});
+                    props.onFinished();
+                }
+            },
+        });
+    };
+
+    const description =
+        _t("You've previously used a newer version of Riot on %(host)s. " +
+            "To use this version again with end to end encryption, you will " +
+            "need to sign out and back in again. ",
+            {host: props.host},
+        );
+
+    const BaseDialog = sdk.getComponent('views.dialogs.BaseDialog');
+    const DialogButtons = sdk.getComponent('views.elements.DialogButtons');
+    return (<BaseDialog className="mx_CryptoStoreTooNewDialog"
+        contentId='mx_Dialog_content'
+        title={_t("Incompatible Database")}
+        hasCancel={false}
+        onFinished={props.onFinished}
+    >
+        <div className="mx_Dialog_content" id='mx_Dialog_content'>
+            { description }
+        </div>
+        <DialogButtons primaryButton={_t('Continue With Encryption Disabled')}
+            hasCancel={false}
+            onPrimaryButtonClick={props.onFinished}
+        >
+            <button onClick={_onLogoutClicked} >
+                { _t('Sign out') }
+            </button>
+        </DialogButtons>
+    </BaseDialog>);
+};
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index 572cc0d2b3..06f834503b 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -249,10 +249,11 @@
     "Enable URL previews for this room (only affects you)": "Enable URL previews for this room (only affects you)",
     "Enable URL previews by default for participants in this room": "Enable URL previews by default for participants in this room",
     "Room Colour": "Room Colour",
-    "Pin unread rooms to the top of the room list": "Pin unread rooms to the top of the room list",
     "Pin rooms I'm mentioned in to the top of the room list": "Pin rooms I'm mentioned in to the top of the room list",
+    "Pin unread rooms to the top of the room list": "Pin unread rooms to the top of the room list",
     "Enable widget screenshots on supported widgets": "Enable widget screenshots on supported widgets",
     "Show empty room list headings": "Show empty room list headings",
+    "Show developer tools": "Show developer tools",
     "Collecting app version information": "Collecting app version information",
     "Collecting logs": "Collecting logs",
     "Uploading report": "Uploading report",
@@ -553,6 +554,7 @@
     "Click here to fix": "Click here to fix",
     "To send events of type <eventType/>, you must be a": "To send events of type <eventType/>, you must be a",
     "Upgrade room to version %(ver)s": "Upgrade room to version %(ver)s",
+    "Open Devtools": "Open Devtools",
     "Who can access this room?": "Who can access this room?",
     "Only people who have been invited": "Only people who have been invited",
     "Anyone who knows the room's link, apart from guests": "Anyone who knows the room's link, apart from guests",
@@ -849,6 +851,11 @@
     "Advanced options": "Advanced options",
     "Block users on other matrix homeservers from joining this room": "Block users on other matrix homeservers from joining this room",
     "This setting cannot be changed later!": "This setting cannot be changed later!",
+    "Sign out": "Sign out",
+    "To avoid losing your chat history, you must export your room keys before logging out. You will need to go back to the newer version of Riot to do this": "To avoid losing your chat history, you must export your room keys before logging out. You will need to go back to the newer version of Riot to do this",
+    "You've previously used a newer version of Riot on %(host)s. To use this version again with end to end encryption, you will need to sign out and back in again. ": "You've previously used a newer version of Riot on %(host)s. To use this version again with end to end encryption, you will need to sign out and back in again. ",
+    "Incompatible Database": "Incompatible Database",
+    "Continue With Encryption Disabled": "Continue With Encryption Disabled",
     "Failed to indicate account erasure": "Failed to indicate account erasure",
     "Unknown error": "Unknown error",
     "Incorrect password": "Incorrect password",
@@ -903,7 +910,6 @@
     "Update any local room aliases to point to the new room": "Update any local room aliases to point to the new room",
     "Stop users from speaking in the old version of the room, and post a message advising users to move to the new room": "Stop users from speaking in the old version of the room, and post a message advising users to move to the new room",
     "Put a link back to the old room at the start of the new room so people can see old messages": "Put a link back to the old room at the start of the new room so people can see old messages",
-    "Sign out": "Sign out",
     "Log out and remove encryption keys?": "Log out and remove encryption keys?",
     "Clear Storage and Sign Out": "Clear Storage and Sign Out",
     "Send Logs": "Send Logs",
@@ -927,9 +933,7 @@
     "Username available": "Username available",
     "To get started, please pick a username!": "To get started, please pick a username!",
     "This will be your account name on the <span></span> homeserver, or you can pick a <a>different server</a>.": "This will be your account name on the <span></span> homeserver, or you can pick a <a>different server</a>.",
-    "If you would like to create a Matrix account you can <a>register</a> now.": "If you would like to create a Matrix account you can <a>register</a> now.",
     "If you already have a Matrix account you can <a>log in</a> instead.": "If you already have a Matrix account you can <a>log in</a> instead.",
-    "You are currently using Riot anonymously as a guest.": "You are currently using Riot anonymously as a guest.",
     "You have successfully set a password!": "You have successfully set a password!",
     "You have successfully set a password and an email address!": "You have successfully set a password and an email address!",
     "You can now return to your account after signing out, and sign in on other devices.": "You can now return to your account after signing out, and sign in on other devices.",
@@ -1036,6 +1040,8 @@
     "This Home server does not support communities": "This Home server does not support communities",
     "Failed to load %(groupId)s": "Failed to load %(groupId)s",
     "Couldn't load home page": "Couldn't load home page",
+    "You are currently using Riot anonymously as a guest.": "You are currently using Riot anonymously as a guest.",
+    "If you would like to create a Matrix account you can <a>register</a> now.": "If you would like to create a Matrix account you can <a>register</a> now.",
     "Login": "Login",
     "Failed to reject invitation": "Failed to reject invitation",
     "This room is not public. You will not be able to rejoin without an invite.": "This room is not public. You will not be able to rejoin without an invite.",
@@ -1272,7 +1278,5 @@
     "Import": "Import",
     "Failed to set direct chat tag": "Failed to set direct chat tag",
     "Failed to remove tag %(tagName)s from room": "Failed to remove tag %(tagName)s from room",
-    "Failed to add tag %(tagName)s to room": "Failed to add tag %(tagName)s to room",
-    "Open Devtools": "Open Devtools",
-    "Show developer tools": "Show developer tools"
+    "Failed to add tag %(tagName)s to room": "Failed to add tag %(tagName)s to room"
 }