diff --git a/notebook/notebookapp.py b/notebook/notebookapp.py
index e070069f30..24aa7c2283 100644
--- a/notebook/notebookapp.py
+++ b/notebook/notebookapp.py
@@ -137,16 +137,6 @@ def load_handlers(name):
     mod = __import__(name, fromlist=['default_handlers'])
     return mod.default_handlers
 
-
-class DeprecationHandler(IPythonHandler):
-    def get(self, url_path):
-        self.set_header("Content-Type", 'text/javascript')
-        self.finish("""
-            console.warn('`/static/widgets/js` is deprecated.  Use `nbextensions/widgets/widgets/js` instead.');
-            define(['%s'], function(x) { return x; });
-        """ % url_path_join('nbextensions', 'widgets', 'widgets', url_path.rstrip('.js')))
-        self.log.warning('Deprecated widget Javascript path /static/widgets/js/*.js was used')
-
 #-----------------------------------------------------------------------------
 # The Tornado web application
 #-----------------------------------------------------------------------------
@@ -262,7 +252,6 @@ def init_handlers(self, settings):
         
         # Order matters. The first handler to match the URL will handle the request.
         handlers = []
-        handlers.append((r'/deprecatedwidgets/(.*)', DeprecationHandler))
         handlers.extend(load_handlers('tree.handlers'))
         handlers.extend([(r"/login", settings['login_handler_class'])])
         handlers.extend([(r"/logout", settings['logout_handler_class'])])
@@ -282,21 +271,21 @@ def init_handlers(self, settings):
         handlers.extend(load_handlers('lab.handlers'))
         
         # BEGIN HARDCODED WIDGETS HACK
+        # TODO: Remove on notebook 5.0
         widgets = None
         try:
-            import widgetsnbextension as widgets
+            import widgetsnbextension
         except:
             try:
                 import ipywidgets as widgets
+                handlers.append(
+                    (r"/nbextensions/widgets/(.*)", FileFindHandler, {
+                        'path': widgets.find_static_assets(),
+                        'no_cache_paths': ['/'], # don't cache anything in nbextensions
+                    }),
+                )
             except:
                 app_log.warning('Widgets are unavailable. Please install widgetsnbextension or ipywidgets 4.0')
-        if widgets is not None:
-            handlers.append(
-                (r"/nbextensions/widgets/(.*)", FileFindHandler, {
-                    'path': widgets.find_static_assets(),
-                    'no_cache_paths': ['/'], # don't cache anything in nbextensions
-                }),
-            )
         # END HARDCODED WIDGETS HACK
         
         handlers.append(
diff --git a/notebook/static/base/js/utils.js b/notebook/static/base/js/utils.js
index 873e962499..49178cfd4f 100644
--- a/notebook/static/base/js/utils.js
+++ b/notebook/static/base/js/utils.js
@@ -13,6 +13,16 @@ define([
     // keep track of which extensions have been loaded already
     var extensions_loaded = [];
 
+    /**
+     * Whether or not an extension has been loaded
+     * @param  {string} extension - name of the extension
+     * @return {boolean}            true if loaded already
+     */
+    var is_loaded = function(extension) {
+        var ext_path = "nbextensions/" + extension;
+        return extensions_loaded.indexOf(ext_path) >= 0;
+    };
+
     /**
      * Load a single extension.
      * @param  {string} extension - extension path.
@@ -22,16 +32,16 @@ define([
         return new Promise(function(resolve, reject) {
             var ext_path = "nbextensions/" + extension;
             requirejs([ext_path], function(module) {
-                try {
-                    if (extensions_loaded.indexOf(ext_path) < 0) {
-                        console.log("Loading extension: " + extension);
-                        module.load_ipython_extension();
-                        extensions_loaded.push(ext_path);
+                if (!is_loaded(extension)) {
+                    console.log("Loading extension: " + extension);
+                    if (module.load_ipython_extension) {
+                        Promise.resolve(module.load_ipython_extension()).then(function() {
+                            resolve(module);
+                        }).catch(reject);
                     }
-                    else{
-                        console.log("Loaded extension already: " + extension);
-                    }
-                } finally {
+                    extensions_loaded.push(ext_path);
+                } else {
+                    console.log("Loaded extension already: " + extension);
                     resolve(module);
                 }
             }, function(err) {
@@ -54,8 +64,8 @@ define([
 
     /**
      * Return a list of extensions that should be active
-     * The config for nbextensions comes in as a dict where keys are 
-     * nbextensions paths and the values are a bool indicating if it 
+     * The config for nbextensions comes in as a dict where keys are
+     * nbextensions paths and the values are a bool indicating if it
      * should be active. This returns a list of nbextension paths
      * where the value is true
      */
@@ -72,12 +82,12 @@ define([
      * in a 'load_extensions' key inside it.
      */
     function load_extensions_from_config(section) {
-        section.loaded.then(function() {
+        return section.loaded.then(function() {
             if (section.data.load_extensions) {
                 var active = filter_extensions(section.data.load_extensions);
-                load_extensions.apply(this, active);
+                return load_extensions.apply(this, active);
             }
-        });
+        }).catch(utils.reject('Could not load nbextensions from ' + section.section_name + ' config file'));
     }
 
     //============================================================================
@@ -937,6 +947,7 @@ define([
     };
 
     var utils = {
+        is_loaded: is_loaded,
         load_extension: load_extension,
         load_extensions: load_extensions,
         filter_extensions: filter_extensions,
diff --git a/notebook/static/notebook/js/main.js b/notebook/static/notebook/js/main.js
index d972a7f9f7..875d38e275 100644
--- a/notebook/static/notebook/js/main.js
+++ b/notebook/static/notebook/js/main.js
@@ -53,21 +53,12 @@ require([
 
     requirejs(['custom/custom'], function() {});
 
-    // BEGIN HARDCODED WIDGETS HACK
-    // Try to load the new extension
-    utils.load_extension('widgets/extension').catch(function () {
-    // Fallback to the ipywidgets extension
-        utils.load_extension('widgets/notebook/js/extension').catch(function () {
-            console.warn('Widgets are not available.  Please install widgetsnbextension or ipywidgets 4.0');
-        });
-    });
-    // END HARDCODED WIDGETS HACK
-
     // compat with old IPython, remove for IPython > 3.0
     window.CodeMirror = CodeMirror;
 
     // Setup all of the config related things
     
+
     var common_options = {
         ws_url : utils.get_body_data("wsUrl"),
         base_url : utils.get_body_data("baseUrl"),
@@ -187,9 +178,28 @@ require([
       configurable: false
     });
     
-    // Now actually load nbextensions
-    utils.load_extensions_from_config(config_section);
-    utils.load_extensions_from_config(common_config);
+    // Now actually load nbextensionsload_extensions_from_config
+    Promise.all([
+        utils.load_extensions_from_config(config_section),
+        utils.load_extensions_from_config(common_config),
+    ])
+    .catch(function(error) {
+        console.error('Could not load nbextensions from user config files', error);
+    })
+    // BEGIN HARDCODED WIDGETS HACK
+    .then(function() {
+        if (!utils.is_loaded('widgets/extension')) {
+            // Fallback to the ipywidgets extension
+            utils.load_extension('widgets/notebook/js/extension').catch(function () {
+                console.warn('Widgets are not available.  Please install widgetsnbextension or ipywidgets 4.0');
+            });
+        }
+    })
+    .catch(function(error) {
+        console.error('Could not load ipywidgets', error);
+    });
+    // END HARDCODED WIDGETS HACK
+
     notebook.load_notebook(common_options.notebook_path);
 
 });
diff --git a/notebook/templates/lab.html b/notebook/templates/lab.html
index 9d10ce9aea..7fedd8c1b1 100644
--- a/notebook/templates/lab.html
+++ b/notebook/templates/lab.html
@@ -23,7 +23,6 @@
           {% endif %}
             custom : '{{ base_url }}custom',
             nbextensions : '{{ base_url }}nbextensions',
-            widgets : '{{ base_url }}deprecatedwidgets',
             kernelspecs : '{{ base_url }}kernelspecs',
             underscore : 'components/underscore/underscore-min',
             backbone : 'components/backbone/backbone-min',
diff --git a/notebook/templates/page.html b/notebook/templates/page.html
index 1f367fef97..cdec96146a 100644
--- a/notebook/templates/page.html
+++ b/notebook/templates/page.html
@@ -33,7 +33,6 @@
             'auth/js/main': 'auth/js/built/main.min',
             custom : '{{ base_url }}custom',
             nbextensions : '{{ base_url }}nbextensions',
-            widgets : '{{ base_url }}deprecatedwidgets',
             kernelspecs : '{{ base_url }}kernelspecs',
             underscore : 'components/underscore/underscore-min',
             backbone : 'components/backbone/backbone-min',