diff --git a/client/components/Nav.jsx b/client/components/Nav.jsx
index 563a8832..6bfcbae7 100644
--- a/client/components/Nav.jsx
+++ b/client/components/Nav.jsx
@@ -29,7 +29,7 @@ function Nav(props) {
                     if (props.user.authenticated) {
                       props.saveProject();
                     } else {
-                      props.openForceAuthentication();
+                      props.showErrorModal('forceAuthentication');
                     }
                   }}
                 >
@@ -168,7 +168,7 @@ Nav.propTypes = {
   logoutUser: PropTypes.func.isRequired,
   stopSketch: PropTypes.func.isRequired,
   showShareModal: PropTypes.func.isRequired,
-  openForceAuthentication: PropTypes.func.isRequired
+  showErrorModal: PropTypes.func.isRequired
 };
 
 export default Nav;
diff --git a/client/constants.js b/client/constants.js
index 32f24968..baa61b84 100644
--- a/client/constants.js
+++ b/client/constants.js
@@ -106,7 +106,5 @@ export const RESET_JUST_OPENED_PROJECT = 'RESET_JUST_OPENED_PROJECT';
 export const SET_PROJECT_SAVED_TIME = 'SET_PROJECT_SAVED_TIME';
 export const RESET_PROJECT_SAVED_TIME = 'RESET_PROJECT_SAVED_TIME';
 export const SET_PREVIOUS_PATH = 'SET_PREVIOUS_PATH';
-export const OPEN_FORCE_AUTHENTICATION = 'OPEN_FORCE_AUTHENTICATION';
-export const CLOSE_FORCE_AUTHENTICATION = 'CLOSE_FORCE_AUTHENTICATION';
-export const SHOW_AUTHENTICATION_ERROR = 'SHOW_AUTHENTICATION_ERROR';
-export const HIDE_AUTHENTICATION_ERROR = 'HIDE_AUTHENTICATION_ERROR';
+export const SHOW_ERROR_MODAL = 'SHOW_ERROR_MODAL';
+export const HIDE_ERROR_MODAL = 'HIDE_ERROR_MODAL';
diff --git a/client/modules/IDE/actions/ide.js b/client/modules/IDE/actions/ide.js
index 487ac392..0d1b0f4c 100644
--- a/client/modules/IDE/actions/ide.js
+++ b/client/modules/IDE/actions/ide.js
@@ -221,26 +221,15 @@ export function setPreviousPath(path) {
   };
 }
 
-export function openForceAuthentication() {
+export function showErrorModal(modalType) {
   return {
-    type: ActionTypes.OPEN_FORCE_AUTHENTICATION
+    type: ActionTypes.SHOW_ERROR_MODAL,
+    modalType
   };
 }
 
-export function closeForceAuthentication() {
+export function hideErrorModal() {
   return {
-    type: ActionTypes.CLOSE_FORCE_AUTHENTICATION
-  };
-}
-
-export function showAuthenticationError() {
-  return {
-    type: ActionTypes.SHOW_AUTHENTICATION_ERROR
-  };
-}
-
-export function hideAuthenticationError() {
-  return {
-    type: ActionTypes.HIDE_AUTHENTICATION_ERROR
+    type: ActionTypes.HIDE_ERROR_MODAL
   };
 }
diff --git a/client/modules/IDE/actions/project.js b/client/modules/IDE/actions/project.js
index 385e55c8..0ced170a 100644
--- a/client/modules/IDE/actions/project.js
+++ b/client/modules/IDE/actions/project.js
@@ -7,7 +7,7 @@ import { setUnsavedChanges,
   resetJustOpenedProject,
   setProjectSavedTime,
   resetProjectSavedTime,
-  showAuthenticationError } from './ide';
+  showErrorModal } from './ide';
 import moment from 'moment';
 
 const ROOT_URL = location.href.indexOf('localhost') > 0 ? 'http://localhost:8000/api' : '/api';
@@ -21,7 +21,6 @@ export function getProject(id) {
     }
     axios.get(`${ROOT_URL}/projects/${id}`, { withCredentials: true })
       .then(response => {
-        // browserHistory.push(`/projects/${id}`);
         dispatch({
           type: ActionTypes.SET_PROJECT,
           project: response.data,
@@ -74,7 +73,9 @@ export function saveProject(autosave = false) {
         })
         .catch((response) => {
           if (response.status === 403) {
-            dispatch(showAuthenticationError());
+            dispatch(showErrorModal('staleSession'));
+          } else if (response.status === 409) {
+            dispatch(showErrorModal('staleProject'));
           } else {
             dispatch({
               type: ActionTypes.PROJECT_SAVE_FAIL,
@@ -90,8 +91,7 @@ export function saveProject(autosave = false) {
           browserHistory.push(`/${response.data.user.username}/sketches/${response.data.id}`);
           dispatch({
             type: ActionTypes.NEW_PROJECT,
-            name: response.data.name,
-            id: response.data.id,
+            project: response.data,
             owner: response.data.user,
             files: response.data.files
           });
@@ -109,7 +109,7 @@ export function saveProject(autosave = false) {
         })
         .catch(response => {
           if (response.status === 403) {
-            dispatch(showAuthenticationError());
+            dispatch(showErrorModal('staleSession'));
           } else {
             dispatch({
               type: ActionTypes.PROJECT_SAVE_FAIL,
@@ -134,8 +134,7 @@ export function createProject() {
         browserHistory.push(`/${response.data.user.username}/sketches/${response.data.id}`);
         dispatch({
           type: ActionTypes.NEW_PROJECT,
-          name: response.data.name,
-          id: response.data.id,
+          project: response.data,
           owner: response.data.user,
           files: response.data.files
         });
@@ -176,10 +175,8 @@ export function cloneProject() {
         browserHistory.push(`/${response.data.user.username}/sketches/${response.data.id}`);
         dispatch({
           type: ActionTypes.NEW_PROJECT,
-          name: response.data.name,
-          id: response.data.id,
+          project: response.data,
           owner: response.data.user,
-          selectedFile: response.data.selectedFile,
           files: response.data.files
         });
       })
diff --git a/client/modules/IDE/actions/projects.js b/client/modules/IDE/actions/projects.js
index 4c100e35..2561f7c9 100644
--- a/client/modules/IDE/actions/projects.js
+++ b/client/modules/IDE/actions/projects.js
@@ -1,6 +1,6 @@
 import * as ActionTypes from '../../../constants';
 import axios from 'axios';
-import { showAuthenticationError, setPreviousPath } from './ide';
+import { showErrorModal, setPreviousPath } from './ide';
 import { resetProject } from './project';
 
 const ROOT_URL = location.href.indexOf('localhost') > 0 ? 'http://localhost:8000/api' : '/api';
@@ -43,7 +43,7 @@ export function deleteProject(id) {
       })
       .catch(response => {
         if (response.status === 403) {
-          dispatch(showAuthenticationError());
+          dispatch(showErrorModal('staleSession'));
         } else {
           dispatch({
             type: ActionTypes.ERROR,
diff --git a/client/modules/IDE/components/AuthenticationError.jsx b/client/modules/IDE/components/AuthenticationError.jsx
deleted file mode 100644
index 6e11a9f0..00000000
--- a/client/modules/IDE/components/AuthenticationError.jsx
+++ /dev/null
@@ -1,24 +0,0 @@
-import React, { PropTypes } from 'react';
-import { Link } from 'react-router';
-
-function AuthenticationError(props) {
-  return (
-    <section className="authentication-error" tabIndex="0">
-      <header className="authentication-error__header">
-        <h2 className="authentication-error__title">Error</h2>
-      </header>
-      <div className="authentication-error__copy">
-        <p>
-          It looks like you've been logged out. Please&nbsp;
-          <Link to="/login" onClick={props.closeModal}>log in</Link>.
-        </p>
-      </div>
-    </section>
-  );
-}
-
-AuthenticationError.propTypes = {
-  closeModal: PropTypes.func.isRequired
-};
-
-export default AuthenticationError;
diff --git a/client/modules/IDE/components/ErrorModal.jsx b/client/modules/IDE/components/ErrorModal.jsx
new file mode 100644
index 00000000..7cd91f60
--- /dev/null
+++ b/client/modules/IDE/components/ErrorModal.jsx
@@ -0,0 +1,70 @@
+import React, { PropTypes } from 'react';
+import InlineSVG from 'react-inlinesvg';
+const exitUrl = require('../../../images/exit.svg');
+import { Link } from 'react-router';
+
+class ErrorModal extends React.Component {
+  componentDidMount() {
+    this.refs.modal.focus();
+  }
+
+
+  forceAuthentication() {
+    return (
+      <p>
+        In order to save sketches, you must be logged in. Please&nbsp;
+        <Link to="/login" onClick={this.props.closeModal}>Login</Link>
+        &nbsp;or&nbsp;
+        <Link to="/signup" onClick={this.props.closeModal}>Sign Up</Link>.
+      </p>
+    );
+  }
+
+  staleSession() {
+    return (
+      <p>
+        It looks like you've been logged out. Please&nbsp;
+        <Link to="/login" onClick={this.props.closeModal}>log in</Link>.
+      </p>
+    );
+  }
+
+  staleProject() {
+    return (
+      <p>
+        The project you have attempted to save is out of date. Please refresh the page.
+      </p>
+    );
+  }
+
+  render() {
+    return (
+      <section className="error-modal" ref="modal" tabIndex="0">
+        <header className="error-modal__header">
+          <h2 className="error-modal__title">Error</h2>
+          <button className="error-modal__exit-button" onClick={this.props.closeModal}>
+            <InlineSVG src={exitUrl} alt="Close Error Modal" />
+          </button>
+        </header>
+        <div className="error-modal__content">
+          {(() => { // eslint-disable-line
+            if (this.props.type === 'forceAuthentication') {
+              return this.forceAuthentication();
+            } else if (this.props.type === 'staleSession') {
+              return this.staleSession();
+            } else if (this.props.type === 'staleProject') {
+              return this.staleProject();
+            }
+          })()}
+        </div>
+      </section>
+    );
+  }
+}
+
+ErrorModal.propTypes = {
+  type: PropTypes.string,
+  closeModal: PropTypes.func.isRequired
+};
+
+export default ErrorModal;
diff --git a/client/modules/IDE/components/ForceAuthentication.jsx b/client/modules/IDE/components/ForceAuthentication.jsx
deleted file mode 100644
index 531c0e70..00000000
--- a/client/modules/IDE/components/ForceAuthentication.jsx
+++ /dev/null
@@ -1,36 +0,0 @@
-import React, { PropTypes } from 'react';
-import InlineSVG from 'react-inlinesvg';
-const exitUrl = require('../../../images/exit.svg');
-import { Link } from 'react-router';
-
-class ForceAuthentication extends React.Component {
-  componentDidMount() {
-    this.refs.forceAuthentication.focus();
-  }
-
-  render() {
-    return (
-      <section className="force-authentication" ref="forceAuthentication" tabIndex="0">
-        <header className="force-authentication__header">
-          <button className="force-authentication__exit-button" onClick={this.props.closeModal}>
-            <InlineSVG src={exitUrl} alt="Close About Overlay" />
-          </button>
-        </header>
-        <div className="force-authentication__copy">
-          <p>
-            In order to save sketches, you must be logged in. Please&nbsp;
-            <Link to="/login" onClick={this.props.closeModal}>Login</Link>
-            &nbsp;or&nbsp;
-            <Link to="/signup" onClick={this.props.closeModal}>Sign Up</Link>.
-          </p>
-        </div>
-      </section>
-    );
-  }
-}
-
-ForceAuthentication.propTypes = {
-  closeModal: PropTypes.func.isRequired
-};
-
-export default ForceAuthentication;
diff --git a/client/modules/IDE/pages/IDEView.jsx b/client/modules/IDE/pages/IDEView.jsx
index ad209a40..5845be81 100644
--- a/client/modules/IDE/pages/IDEView.jsx
+++ b/client/modules/IDE/pages/IDEView.jsx
@@ -9,8 +9,7 @@ import NewFileModal from '../components/NewFileModal';
 import NewFolderModal from '../components/NewFolderModal';
 import ShareModal from '../components/ShareModal';
 import KeyboardShortcutModal from '../components/KeyboardShortcutModal';
-import ForceAuthentication from '../components/ForceAuthentication';
-import AuthenticationError from '../components/AuthenticationError';
+import ErrorModal from '../components/ErrorModal';
 import Nav from '../../../components/Nav';
 import Console from '../components/Console';
 import Toast from '../components/Toast';
@@ -195,7 +194,7 @@ class IDEView extends React.Component {
           logoutUser={this.props.logoutUser}
           stopSketch={this.props.stopSketch}
           showShareModal={this.props.showShareModal}
-          openForceAuthentication={this.props.openForceAuthentication}
+          showErrorModal={this.props.showErrorModal}
           unsavedChanges={this.props.ide.unsavedChanges}
           warnIfUnsavedChanges={this.warnIfUnsavedChanges}
         />
@@ -425,22 +424,12 @@ class IDEView extends React.Component {
           }
         })()}
         {(() => { // eslint-disable-line
-          if (this.props.ide.forceAuthenticationVisible) {
+          if (this.props.ide.errorType) {
             return (
               <Overlay>
-                <ForceAuthentication
-                  closeModal={this.props.closeForceAuthentication}
-                />
-              </Overlay>
-            );
-          }
-        })()}
-        {(() => { // eslint-disable-line
-          if (this.props.ide.authenticationError) {
-            return (
-              <Overlay>
-                <AuthenticationError
-                  closeModal={this.props.hideAuthenticationError}
+                <ErrorModal
+                  type={this.props.ide.errorType}
+                  closeModal={this.props.hideErrorModal}
                 />
               </Overlay>
             );
@@ -488,9 +477,8 @@ IDEView.propTypes = {
     infiniteLoopMessage: PropTypes.string.isRequired,
     projectSavedTime: PropTypes.string.isRequired,
     previousPath: PropTypes.string.isRequired,
-    forceAuthenticationVisible: PropTypes.bool.isRequired,
-    authenticationError: PropTypes.bool.isRequired,
-    justOpenedProject: PropTypes.bool.isRequired
+    justOpenedProject: PropTypes.bool.isRequired,
+    errorType: PropTypes.string
   }).isRequired,
   startSketch: PropTypes.func.isRequired,
   stopSketch: PropTypes.func.isRequired,
@@ -590,11 +578,10 @@ IDEView.propTypes = {
   setBlobUrl: PropTypes.func.isRequired,
   setPreviousPath: PropTypes.func.isRequired,
   resetProject: PropTypes.func.isRequired,
-  closeForceAuthentication: PropTypes.func.isRequired,
-  openForceAuthentication: PropTypes.func.isRequired,
   console: PropTypes.array.isRequired,
   clearConsole: PropTypes.func.isRequired,
-  hideAuthenticationError: PropTypes.func.isRequired
+  showErrorModal: PropTypes.func.isRequired,
+  hideErrorModal: PropTypes.func.isRequired
 };
 
 function mapStateToProps(state) {
diff --git a/client/modules/IDE/reducers/ide.js b/client/modules/IDE/reducers/ide.js
index 5c01c142..f4908f2a 100644
--- a/client/modules/IDE/reducers/ide.js
+++ b/client/modules/IDE/reducers/ide.js
@@ -19,8 +19,7 @@ const initialState = {
   justOpenedProject: false,
   projectSavedTime: '',
   previousPath: '/',
-  forceAuthenticationVisible: false,
-  authenticationError: false
+  errorType: undefined
 };
 
 const ide = (state = initialState, action) => {
@@ -93,14 +92,10 @@ const ide = (state = initialState, action) => {
       return Object.assign({}, state, { projectSavedTime: '' });
     case ActionTypes.SET_PREVIOUS_PATH:
       return Object.assign({}, state, { previousPath: action.path });
-    case ActionTypes.OPEN_FORCE_AUTHENTICATION:
-      return Object.assign({}, state, { forceAuthenticationVisible: true });
-    case ActionTypes.CLOSE_FORCE_AUTHENTICATION:
-      return Object.assign({}, state, { forceAuthenticationVisible: false });
-    case ActionTypes.SHOW_AUTHENTICATION_ERROR:
-      return Object.assign({}, state, { authenticationError: true });
-    case ActionTypes.HIDE_AUTHENTICATION_ERROR:
-      return Object.assign({}, state, { authenticationError: false });
+    case ActionTypes.SHOW_ERROR_MODAL:
+      return Object.assign({}, state, { errorType: action.modalType });
+    case ActionTypes.HIDE_ERROR_MODAL:
+      return Object.assign({}, state, { errorType: undefined });
     default:
       return state;
   }
diff --git a/client/modules/IDE/reducers/project.js b/client/modules/IDE/reducers/project.js
index 7d4df05e..2a89d519 100644
--- a/client/modules/IDE/reducers/project.js
+++ b/client/modules/IDE/reducers/project.js
@@ -18,14 +18,16 @@ const project = (state, action) => {
       return Object.assign({}, { ...state }, { name: action.name });
     case ActionTypes.NEW_PROJECT:
       return {
-        id: action.id,
-        name: action.name,
+        id: action.project.id,
+        name: action.project.name,
+        updatedAt: action.project.updatedAt,
         owner: action.owner
       };
     case ActionTypes.SET_PROJECT:
       return {
         id: action.project.id,
         name: action.project.name,
+        updatedAt: action.project.updatedAt,
         owner: action.owner
       };
     case ActionTypes.RESET_PROJECT:
diff --git a/client/modules/User/actions.js b/client/modules/User/actions.js
index 3eaeb0fd..21617ac5 100644
--- a/client/modules/User/actions.js
+++ b/client/modules/User/actions.js
@@ -1,7 +1,7 @@
 import * as ActionTypes from '../../constants';
 import { browserHistory } from 'react-router';
 import axios from 'axios';
-import { showAuthenticationError, justOpenedProject } from '../IDE/actions/ide';
+import { showErrorModal, justOpenedProject } from '../IDE/actions/ide';
 
 
 const ROOT_URL = location.href.indexOf('localhost') > 0 ? 'http://localhost:8000/api' : '/api';
@@ -91,12 +91,12 @@ export function validateSession() {
       .then(response => {
         const state = getState();
         if (state.user.username !== response.data.username) {
-          dispatch(showAuthenticationError());
+          dispatch(showErrorModal('staleSession'));
         }
       })
       .catch(response => {
         if (response.status === 404) {
-          dispatch(showAuthenticationError());
+          dispatch(showErrorModal('staleSession'));
         }
       });
   };
diff --git a/client/styles/components/_authentication-error.scss b/client/styles/components/_authentication-error.scss
deleted file mode 100644
index 5b45e14a..00000000
--- a/client/styles/components/_authentication-error.scss
+++ /dev/null
@@ -1,13 +0,0 @@
-.authentication-error {
-  @extend %modal; 
-}
-
-.authentication-error__header {
-  padding: #{20 / $base-font-size}rem;
-}
-
-.authentication-error__copy {
-  padding: #{20 / $base-font-size}rem;
-  padding-top: 0;
-  padding-bottom: #{60 / $base-font-size}rem;
-}
\ No newline at end of file
diff --git a/client/styles/components/_force-authentication.scss b/client/styles/components/_error-modal.scss
similarity index 65%
rename from client/styles/components/_force-authentication.scss
rename to client/styles/components/_error-modal.scss
index b75d87eb..35eb940f 100644
--- a/client/styles/components/_force-authentication.scss
+++ b/client/styles/components/_error-modal.scss
@@ -1,24 +1,24 @@
-.force-authentication {
+.error-modal {
   @extend %modal;
   display: flex;
   flex-wrap: wrap;
   flex-flow: column;
 }
 
-.force-authentication__header {
+.error-modal__header {
   display: flex;
-  justify-content: flex-end;
+  justify-content: space-between;
   padding: #{20 / $base-font-size}rem;
 }
 
-.force-authentication__exit-button {
+.error-modal__exit-button {
   @include themify() {
     @extend %icon;
   }
 }
 
-.force-authentication__copy {
+.error-modal__content {
   padding: #{20 / $base-font-size}rem;
   padding-top: 0;
   padding-bottom: #{60 / $base-font-size}rem;
-}
\ No newline at end of file
+}
diff --git a/client/styles/main.scss b/client/styles/main.scss
index 823c0e89..d5a507a6 100644
--- a/client/styles/main.scss
+++ b/client/styles/main.scss
@@ -30,10 +30,8 @@
 @import 'components/forms';
 @import 'components/toast';
 @import 'components/timer';
-@import 'components/force-authentication';
 @import 'components/form-container';
-@import 'components/uploader';
-@import 'components/authentication-error';
+@import 'components/error-modal';
 
 @import 'layout/ide';
 @import 'layout/fullscreen';
diff --git a/server/controllers/project.controller.js b/server/controllers/project.controller.js
index db401e41..0d3c9e9e 100644
--- a/server/controllers/project.controller.js
+++ b/server/controllers/project.controller.js
@@ -2,6 +2,7 @@ import Project from '../models/project';
 import User from '../models/user';
 import archiver from 'archiver';
 import request from 'request';
+import moment from 'moment';
 
 
 export function createProject(req, res) {
@@ -29,7 +30,10 @@ export function createProject(req, res) {
 export function updateProject(req, res) {
   Project.findById(req.params.project_id, (err, project) => {
     if (!req.user || !project.user.equals(req.user._id)) {
-      return res.status(403).send({ success: false, message: 'Session does not match owner of project.'});
+      return res.status(403).send({ success: false, message: 'Session does not match owner of project.' });
+    }
+    if (req.body.updatedAt && moment(req.body.updatedAt) < moment(project.updatedAt)) {
+      return res.status(409).send({ success: false, message: 'Attempted to save stale version of project.' })
     }
     Project.findByIdAndUpdate(req.params.project_id,
       {