diff --git a/src/MatrixClientPeg.js b/src/MatrixClientPeg.js
index b31cf7511e..4264828c7b 100644
--- a/src/MatrixClientPeg.js
+++ b/src/MatrixClientPeg.js
@@ -78,6 +78,18 @@ class MatrixClientPeg {
     }
 
     async start() {
+        // try to initialise e2e on the new client
+        try {
+            // check that we have a version of the js-sdk which includes initCrypto
+            if (this.matrixClient.initCrypto) {
+                await this.matrixClient.initCrypto();
+            }
+        } catch(e) {
+            // 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);
+        }
+
         const opts = utils.deepCopy(this.opts);
         // the react sdk doesn't work without this, so don't allow
         opts.pendingEventOrdering = "detached";
diff --git a/src/SlashCommands.js b/src/SlashCommands.js
index b1cd59f3a9..dea3d27751 100644
--- a/src/SlashCommands.js
+++ b/src/SlashCommands.js
@@ -301,51 +301,54 @@ const commands = {
                 const deviceId = matches[2];
                 const fingerprint = matches[3];
 
-                const device = MatrixClientPeg.get().getStoredDevice(userId, deviceId);
-                if (!device) {
-                    return reject(_t(`Unknown (user, device) pair:`) + ` (${userId}, ${deviceId})`);
-                }
+                return success(
+                    // Promise.resolve to handle transition from static result to promise; can be removed
+                    // in future
+                    Promise.resolve(MatrixClientPeg.get().getStoredDevice(userId, deviceId)).then((device) => {
+                        if (!device) {
+                            throw new Error(_t(`Unknown (user, device) pair:`) + ` (${userId}, ${deviceId})`);
+                        }
 
-                if (device.isVerified()) {
-                    if (device.getFingerprint() === fingerprint) {
-                        return reject(_t(`Device already verified!`));
-                    } else {
-                        return reject(_t(`WARNING: Device already verified, but keys do NOT MATCH!`));
-                    }
-                }
+                        if (device.isVerified()) {
+                            if (device.getFingerprint() === fingerprint) {
+                                throw new Error(_t(`Device already verified!`));
+                            } else {
+                                throw new Error(_t(`WARNING: Device already verified, but keys do NOT MATCH!`));
+                            }
+                        }
 
-                if (device.getFingerprint() === fingerprint) {
-                    MatrixClientPeg.get().setDeviceVerified(
-                        userId, deviceId, true,
-                    );
+                        if (device.getFingerprint() !== fingerprint) {
+                            const fprint = device.getFingerprint();
+                            throw new Error(
+                                _t('WARNING: KEY VERIFICATION FAILED! The signing key for %(userId)s and device' +
+                                   ' %(deviceId)s is "%(fprint)s" which does not match the provided key' +
+                                   ' "%(fingerprint)s". This could mean your communications are being intercepted!',
+                                   {deviceId: deviceId, fprint: fprint, userId: userId, fingerprint: fingerprint}));
+                        }
 
-                    // Tell the user we verified everything!
-                    const QuestionDialog = sdk.getComponent("dialogs.QuestionDialog");
-                    Modal.createDialog(QuestionDialog, {
-                        title: _t("Verified key"),
-                        description: (
-                            <div>
-                                <p>
-                                {
-                                    _t("The signing key you provided matches the signing key you received " +
-                                    "from %(userId)s's device %(deviceId)s. Device marked as verified.",
-                                    {userId: userId, deviceId: deviceId})
-                                }
-                                </p>
-                            </div>
-                        ),
-                        hasCancelButton: false,
-                    });
-
-                    return success();
-                } else {
-                    const fprint = device.getFingerprint();
-                    return reject(
-                        _t('WARNING: KEY VERIFICATION FAILED! The signing key for %(userId)s and device' +
-                           ' %(deviceId)s is "%(fprint)s" which does not match the provided key' +
-                           ' "%(fingerprint)s". This could mean your communications are being intercepted!',
-                            {deviceId: deviceId, fprint: fprint, userId: userId, fingerprint: fingerprint}));
-                }
+                        return MatrixClientPeg.get().setDeviceVerified(
+                            userId, deviceId, true,
+                        );
+                    }).then(() => {
+                        // Tell the user we verified everything
+                        const QuestionDialog = sdk.getComponent("dialogs.QuestionDialog");
+                        Modal.createDialog(QuestionDialog, {
+                            title: _t("Verified key"),
+                            description: (
+                                <div>
+                                  <p>
+                                    {
+                                        _t("The signing key you provided matches the signing key you received " +
+                                           "from %(userId)s's device %(deviceId)s. Device marked as verified.",
+                                           {userId: userId, deviceId: deviceId})
+                                    }
+                                  </p>
+                                </div>
+                            ),
+                            hasCancelButton: false,
+                        });
+                    }),
+                );
             }
         }
         return reject(this.getUsage());
diff --git a/src/async-components/views/dialogs/EncryptedEventDialog.js b/src/async-components/views/dialogs/EncryptedEventDialog.js
index 3a6ca4e6b7..cec2f05de2 100644
--- a/src/async-components/views/dialogs/EncryptedEventDialog.js
+++ b/src/async-components/views/dialogs/EncryptedEventDialog.js
@@ -28,23 +28,31 @@ module.exports = React.createClass({
     },
 
     getInitialState: function() {
-        return { device: this.refreshDevice() };
+        return { device: null };
     },
 
     componentWillMount: function() {
         this._unmounted = false;
         var client = MatrixClientPeg.get();
-        client.on("deviceVerificationChanged", this.onDeviceVerificationChanged);
 
-        // no need to redownload keys if we already have the device
-        if (this.state.device) {
-            return;
-        }
-        client.downloadKeys([this.props.event.getSender()], true).done(()=>{
+        // first try to load the device from our store.
+        //
+        this.refreshDevice().then((dev) => {
+            if (dev) {
+                return dev;
+            }
+
+            // tell the client to try to refresh the device list for this user
+            return client.downloadKeys([this.props.event.getSender()], true).then(() => {
+                return this.refreshDevice();
+            });
+        }).then((dev) => {
             if (this._unmounted) {
                 return;
             }
-            this.setState({ device: this.refreshDevice() });
+
+            this.setState({ device: dev });
+            client.on("deviceVerificationChanged", this.onDeviceVerificationChanged);
         }, (err)=>{
             console.log("Error downloading devices", err);
         });
@@ -59,12 +67,16 @@ module.exports = React.createClass({
     },
 
     refreshDevice: function() {
-        return MatrixClientPeg.get().getEventSenderDeviceInfo(this.props.event);
+        // Promise.resolve to handle transition from static result to promise; can be removed
+        // in future
+        return Promise.resolve(MatrixClientPeg.get().getEventSenderDeviceInfo(this.props.event));
     },
 
     onDeviceVerificationChanged: function(userId, device) {
         if (userId == this.props.event.getSender()) {
-            this.setState({ device: this.refreshDevice() });
+            this.refreshDevice().then((dev) => {
+                this.setState({ device: dev });
+            });
         }
     },
 
diff --git a/src/components/views/rooms/EventTile.js b/src/components/views/rooms/EventTile.js
index bb085279e8..68ef3a1f44 100644
--- a/src/components/views/rooms/EventTile.js
+++ b/src/components/views/rooms/EventTile.js
@@ -193,13 +193,12 @@ module.exports = withMatrixClient(React.createClass({
         }
     },
 
-    _verifyEvent: function(mxEvent) {
-        var verified = null;
-
-        if (mxEvent.isEncrypted()) {
-            verified = this.props.matrixClient.isEventSenderVerified(mxEvent);
+    _verifyEvent: async function(mxEvent) {
+        if (!mxEvent.isEncrypted()) {
+            return;
         }
 
+        const verified = await this.props.matrixClient.isEventSenderVerified(mxEvent);
         this.setState({
             verified: verified
         });
diff --git a/src/components/views/rooms/MemberInfo.js b/src/components/views/rooms/MemberInfo.js
index c034f0e704..290bd35483 100644
--- a/src/components/views/rooms/MemberInfo.js
+++ b/src/components/views/rooms/MemberInfo.js
@@ -136,8 +136,12 @@ module.exports = withMatrixClient(React.createClass({
         if (userId == this.props.member.userId) {
             // no need to re-download the whole thing; just update our copy of
             // the list.
-            var devices = this.props.matrixClient.getStoredDevicesForUser(userId);
-            this.setState({devices: devices});
+
+            // Promise.resolve to handle transition from static result to promise; can be removed
+            // in future
+            Promise.resolve(this.props.matrixClient.getStoredDevicesForUser(userId)).then((devices) => {
+                this.setState({devices: devices});
+            });
         }
     },
 
@@ -204,14 +208,15 @@ module.exports = withMatrixClient(React.createClass({
 
         var client = this.props.matrixClient;
         var self = this;
-        client.downloadKeys([member.userId], true).finally(function() {
+        client.downloadKeys([member.userId], true).then(() => {
+            return client.getStoredDevicesForUser(member.userId);
+        }).finally(function() {
             self._cancelDeviceList = null;
-        }).done(function() {
+        }).done(function(devices) {
             if (cancelled) {
                 // we got cancelled - presumably a different user now
                 return;
             }
-            var devices = client.getStoredDevicesForUser(member.userId);
             self._disambiguateDevices(devices);
             self.setState({devicesLoading: false, devices: devices});
         }, function(err) {