diff --git a/web/app.react.js b/web/app.react.js
index 61f6a964e..29e38efea 100644
--- a/web/app.react.js
+++ b/web/app.react.js
@@ -1,281 +1,283 @@
 // @flow
 
 import 'basscss/css/basscss.min.css';
 import './theme.css';
 import { config as faConfig } from '@fortawesome/fontawesome-svg-core';
 import _isEqual from 'lodash/fp/isEqual';
 import * as React from 'react';
 import { DndProvider } from 'react-dnd';
 import { HTML5Backend } from 'react-dnd-html5-backend';
 import { useDispatch } from 'react-redux';
 
 import {
   fetchEntriesActionTypes,
   updateCalendarQueryActionTypes,
 } from 'lib/actions/entry-actions';
 import {
   createLoadingStatusSelector,
   combineLoadingStatuses,
 } from 'lib/selectors/loading-selectors';
 import { unreadCount } from 'lib/selectors/thread-selectors';
 import { isLoggedIn } from 'lib/selectors/user-selectors';
 import type { LoadingStatus } from 'lib/types/loading-types';
 import type { Dispatch } from 'lib/types/redux-types';
 import { registerConfig } from 'lib/utils/config';
 
 import AppsDirectory from './apps/apps-directory.react';
 import Calendar from './calendar/calendar.react';
 import Chat from './chat/chat.react';
 import NavigationArrows from './components/navigation-arrows.react';
 import InputStateContainer from './input/input-state-container.react';
 import LoadingIndicator from './loading-indicator.react';
 import { MenuProvider } from './menu-provider.react';
 import { ModalProvider, useModalContext } from './modals/modal-provider.react';
+import DeviceIDUpdater from './redux/device-id-updater';
 import DisconnectedBar from './redux/disconnected-bar';
 import DisconnectedBarVisibilityHandler from './redux/disconnected-bar-visibility-handler';
 import FocusHandler from './redux/focus-handler.react';
 import { useSelector } from './redux/redux-utils';
 import VisibilityHandler from './redux/visibility-handler.react';
 import history from './router-history';
 import AccountSettings from './settings/account-settings.react';
 import DangerZone from './settings/danger-zone.react';
 import LeftLayoutAside from './sidebar/left-layout-aside.react';
 import Splash from './splash/splash.react';
 import './typography.css';
 import css from './style.css';
 import getTitle from './title/getTitle';
 import { type NavInfo, updateNavInfoActionType } from './types/nav-types';
 import { canonicalURLFromReduxState, navInfoFromURL } from './url-utils';
 
 // We want Webpack's css-loader and style-loader to handle the Fontawesome CSS,
 // so we disable the autoAddCss logic and import the CSS file. Otherwise every
 // icon flashes huge for a second before the CSS is loaded.
 import '@fortawesome/fontawesome-svg-core/styles.css';
 faConfig.autoAddCss = false;
 
 registerConfig({
   // We can't securely cache credentials on web, so we have no way to recover
   // from a cookie invalidation
   resolveInvalidatedCookie: null,
   // We use httponly cookies on web to protect against XSS attacks, so we have
   // no access to the cookies from JavaScript
   setCookieOnRequest: false,
   setSessionIDOnRequest: true,
   // Never reset the calendar range
   calendarRangeInactivityLimit: null,
   platformDetails: { platform: 'web' },
 });
 
 type BaseProps = {
   +location: {
     +pathname: string,
     ...
   },
 };
 type Props = {
   ...BaseProps,
   // Redux state
   +navInfo: NavInfo,
   +entriesLoadingStatus: LoadingStatus,
   +loggedIn: boolean,
   +activeThreadCurrentlyUnread: boolean,
   // Redux dispatch functions
   +dispatch: Dispatch,
   +modals: $ReadOnlyArray<React.Node>,
 };
 class App extends React.PureComponent<Props> {
   componentDidMount() {
     const {
       navInfo,
       location: { pathname },
       loggedIn,
     } = this.props;
     const newURL = canonicalURLFromReduxState(navInfo, pathname, loggedIn);
     if (pathname !== newURL) {
       history.replace(newURL);
     }
   }
 
   componentDidUpdate(prevProps: Props) {
     const {
       navInfo,
       location: { pathname },
       loggedIn,
     } = this.props;
     if (!_isEqual(navInfo)(prevProps.navInfo)) {
       const newURL = canonicalURLFromReduxState(navInfo, pathname, loggedIn);
       if (newURL !== pathname) {
         history.push(newURL);
       }
     } else if (pathname !== prevProps.location.pathname) {
       const newNavInfo = navInfoFromURL(pathname, { navInfo });
       if (!_isEqual(newNavInfo)(navInfo)) {
         this.props.dispatch({
           type: updateNavInfoActionType,
           payload: newNavInfo,
         });
       }
     } else if (loggedIn !== prevProps.loggedIn) {
       const newURL = canonicalURLFromReduxState(navInfo, pathname, loggedIn);
       if (newURL !== pathname) {
         history.replace(newURL);
       }
     }
   }
 
   onWordmarkClicked = () => {
     this.props.dispatch({
       type: updateNavInfoActionType,
       payload: { tab: 'chat' },
     });
   };
 
   render() {
     let content;
     if (this.props.loggedIn) {
       content = this.renderMainContent();
     } else {
       content = <Splash />;
     }
     return (
       <DndProvider backend={HTML5Backend}>
         <MenuProvider>
           <FocusHandler />
           <VisibilityHandler />
+          <DeviceIDUpdater />
           {content}
           {this.props.modals}
         </MenuProvider>
       </DndProvider>
     );
   }
 
   renderMainContent() {
     let mainContent;
     const { tab, settingsSection } = this.props.navInfo;
     if (tab === 'calendar') {
       mainContent = <Calendar url={this.props.location.pathname} />;
     } else if (tab === 'chat') {
       mainContent = <Chat />;
     } else if (tab === 'apps') {
       mainContent = <AppsDirectory />;
     } else if (tab === 'settings') {
       if (settingsSection === 'account') {
         mainContent = <AccountSettings />;
       } else if (settingsSection === 'danger-zone') {
         mainContent = <DangerZone />;
       }
     }
 
     const shouldShowNavigationArrows = false;
     let navigationArrows = null;
     if (shouldShowNavigationArrows) {
       navigationArrows = <NavigationArrows />;
     }
 
     return (
       <div className={css.layout}>
         <DisconnectedBarVisibilityHandler />
         <DisconnectedBar />
         <header className={css['header']}>
           <div className={css['main-header']}>
             <h1 className={css.wordmark}>
               <a
                 title="Comm Home"
                 aria-label="Go to Comm Home"
                 onClick={this.onWordmarkClicked}
               >
                 Comm
               </a>
             </h1>
             {navigationArrows}
             <div className={css['upper-right']}>
               <LoadingIndicator
                 status={this.props.entriesLoadingStatus}
                 size="medium"
                 loadingClassName={css['page-loading']}
                 errorClassName={css['page-error']}
               />
             </div>
           </div>
         </header>
         <InputStateContainer>
           <div className={css['main-content-container']}>
             <div className={css['main-content']}>{mainContent}</div>
           </div>
         </InputStateContainer>
         <LeftLayoutAside />
       </div>
     );
   }
 }
 
 const fetchEntriesLoadingStatusSelector = createLoadingStatusSelector(
   fetchEntriesActionTypes,
 );
 const updateCalendarQueryLoadingStatusSelector = createLoadingStatusSelector(
   updateCalendarQueryActionTypes,
 );
 
 const ConnectedApp: React.ComponentType<BaseProps> = React.memo<BaseProps>(
   function ConnectedApp(props) {
     const activeChatThreadID = useSelector(
       state => state.navInfo.activeChatThreadID,
     );
     const navInfo = useSelector(state => state.navInfo);
 
     const fetchEntriesLoadingStatus = useSelector(
       fetchEntriesLoadingStatusSelector,
     );
     const updateCalendarQueryLoadingStatus = useSelector(
       updateCalendarQueryLoadingStatusSelector,
     );
     const entriesLoadingStatus = combineLoadingStatuses(
       fetchEntriesLoadingStatus,
       updateCalendarQueryLoadingStatus,
     );
 
     const loggedIn = useSelector(isLoggedIn);
     const activeThreadCurrentlyUnread = useSelector(
       state =>
         !activeChatThreadID ||
         !!state.threadStore.threadInfos[activeChatThreadID]?.currentUser.unread,
     );
 
     const boundUnreadCount = useSelector(unreadCount);
     React.useEffect(() => {
       document.title = getTitle(boundUnreadCount);
     }, [boundUnreadCount]);
 
     const dispatch = useDispatch();
     const modalContext = useModalContext();
     const modals = React.useMemo(
       () =>
         modalContext.modals.map(([modal, key]) => (
           <React.Fragment key={key}>{modal}</React.Fragment>
         )),
       [modalContext.modals],
     );
 
     return (
       <App
         {...props}
         navInfo={navInfo}
         entriesLoadingStatus={entriesLoadingStatus}
         loggedIn={loggedIn}
         activeThreadCurrentlyUnread={activeThreadCurrentlyUnread}
         dispatch={dispatch}
         modals={modals}
       />
     );
   },
 );
 
 function AppWithProvider(props: BaseProps): React.Node {
   return (
     <ModalProvider>
       <ConnectedApp {...props} />
     </ModalProvider>
   );
 }
 
 export default AppWithProvider;
diff --git a/web/redux/device-id-reducer.js b/web/redux/device-id-reducer.js
index bef6b6279..8430446fe 100644
--- a/web/redux/device-id-reducer.js
+++ b/web/redux/device-id-reducer.js
@@ -1,15 +1,28 @@
 // @flow
 
+import {
+  deleteAccountActionTypes,
+  logOutActionTypes,
+} from 'lib/actions/user-actions.js';
+import { setNewSessionActionType } from 'lib/utils/action-utils.js';
+
 import type { Action } from '../redux/redux-setup';
 import { deviceIDFormatRegex } from '../utils/device-id';
 import { setDeviceIDActionType } from './action-types';
 
 export function reduceDeviceID(state: ?string, action: Action): ?string {
   if (action.type === setDeviceIDActionType) {
     if (action.payload?.match(deviceIDFormatRegex)) {
       return action.payload;
     }
     return null;
+  } else if (
+    action.type === logOutActionTypes.success ||
+    action.type === deleteAccountActionTypes.success ||
+    (action.type === setNewSessionActionType &&
+      action.payload.sessionChange.cookieInvalidated)
+  ) {
+    return null;
   }
   return state;
 }
diff --git a/web/redux/device-id-updater.js b/web/redux/device-id-updater.js
new file mode 100644
index 000000000..4cbf0e445
--- /dev/null
+++ b/web/redux/device-id-updater.js
@@ -0,0 +1,28 @@
+// @flow
+import * as React from 'react';
+import { useDispatch, useSelector } from 'react-redux';
+
+import { generateDeviceID, deviceIDTypes } from '../utils/device-id';
+import { setDeviceIDActionType } from './action-types';
+
+function DeviceIDUpdater(): null {
+  const dispatch = useDispatch();
+  const deviceID = useSelector(state => state.deviceID);
+  const hasDeviceID = !!deviceID;
+  const hadDeviceIDRef = React.useRef<?boolean>(null);
+
+  React.useEffect(() => {
+    if (hadDeviceIDRef.current !== false && !hasDeviceID) {
+      const newDeviceID = generateDeviceID(deviceIDTypes.WEB);
+      dispatch({
+        type: setDeviceIDActionType,
+        payload: newDeviceID,
+      });
+    }
+    hadDeviceIDRef.current = hasDeviceID;
+  }, [hasDeviceID, dispatch]);
+
+  return null;
+}
+
+export default DeviceIDUpdater;