diff --git a/IPython/html/notebookapp.py b/IPython/html/notebookapp.py
index 2641ca9e7..8a3a2213d 100644
--- a/IPython/html/notebookapp.py
+++ b/IPython/html/notebookapp.py
@@ -665,7 +665,7 @@ class NotebookApp(BaseIPythonApplication):
         help='The config manager class to use'
     )
 
-    kernel_spec_manager = Instance(KernelSpecManager)
+    kernel_spec_manager = Instance(KernelSpecManager, allow_none=True)
 
     kernel_spec_manager_class = Type(
         default_value=KernelSpecManager,
diff --git a/IPython/html/services/clusters/clustermanager.py b/IPython/html/services/clusters/clustermanager.py
index c0a877613..f42827399 100644
--- a/IPython/html/services/clusters/clustermanager.py
+++ b/IPython/html/services/clusters/clustermanager.py
@@ -20,7 +20,7 @@ class ClusterManager(LoggingConfigurable):
     delay = Float(1., config=True,
         help="delay (in s) between starting the controller and the engines")
 
-    loop = Instance('zmq.eventloop.ioloop.IOLoop')
+    loop = Instance('zmq.eventloop.ioloop.IOLoop', allow_none=True)
     def _loop_default(self):
         from zmq.eventloop.ioloop import IOLoop
         return IOLoop.instance()
diff --git a/IPython/html/widgets/widget.py b/IPython/html/widgets/widget.py
index 417acd714..5c9ec6106 100644
--- a/IPython/html/widgets/widget.py
+++ b/IPython/html/widgets/widget.py
@@ -129,7 +129,7 @@ class Widget(LoggingConfigurable):
         If empty, look in the global registry.""", sync=True)
     _view_name = Unicode(None, allow_none=True, help="""Default view registered in the front-end
         to use to represent the widget.""", sync=True)
-    comm = Instance('IPython.kernel.comm.Comm')
+    comm = Instance('IPython.kernel.comm.Comm', allow_none=True)
     
     msg_throttle = Int(3, sync=True, help="""Maximum number of msgs the 
         front-end can send before receiving an idle msg from the back-end.""")