diff --git a/src/calibre/customize/builtins.py b/src/calibre/customize/builtins.py
index 6abf7b4808..fb06ce4115 100644
--- a/src/calibre/customize/builtins.py
+++ b/src/calibre/customize/builtins.py
@@ -1048,6 +1048,11 @@ class InputOptions(PreferencesPlugin):
     config_widget = 'calibre.gui2.preferences.conversion:InputOptions'
     description = _('Set conversion options specific to each input format')
 
+    def create_widget(self, *args, **kwargs):
+        # The DOC Input plugin tries to override this
+        self.config_widget = 'calibre.gui2.preferences.conversion:InputOptions'
+        return PreferencesPlugin.create_widget(self, *args, **kwargs)
+
 class CommonOptions(PreferencesPlugin):
     name = 'Common Options'
     icon = I('convert.png')
diff --git a/src/calibre/gui2/convert/__init__.py b/src/calibre/gui2/convert/__init__.py
index 3e2a8bde3d..a642bc6cca 100644
--- a/src/calibre/gui2/convert/__init__.py
+++ b/src/calibre/gui2/convert/__init__.py
@@ -27,13 +27,14 @@ def config_widget_for_input_plugin(plugin):
                 'calibre.gui2.convert.'+name).PluginWidget
     except ImportError:
         # If this is not a builtin plugin, we have to import it differently
-        try:
-            ans = importlib.import_module(plugin.__module__+'.'+name).PluginWidget
-        except (ImportError, AttributeError, TypeError):
-            pass
-        else:
-            if issubclass(ans, Widget):
-                return ans
+        if plugin.__module__ and plugin.__module__.startswith('calibre_plugins.'):
+            try:
+                ans = importlib.import_module(plugin.__module__+'.'+name).PluginWidget
+            except (ImportError, AttributeError, TypeError):
+                pass
+            else:
+                if issubclass(ans, Widget):
+                    return ans
 
 def bulk_defaults_for_input_format(fmt):
     plugin = plugin_for_input_format(fmt)