diff --git a/juju/client/connector.py b/juju/client/connector.py
index ca490910..6c494732 100644
--- a/juju/client/connector.py
+++ b/juju/client/connector.py
@@ -5,12 +5,14 @@
 import logging
 
 import macaroonbakery.httpbakery as httpbakery
+
+from juju.client import client
 from juju.client.connection import Connection
 from juju.client.gocookies import GoCookieJar, go_to_py_cookie
-from juju.client.jujudata import FileJujuData, API_ENDPOINTS_KEY
+from juju.client.jujudata import API_ENDPOINTS_KEY, FileJujuData
 from juju.client.proxy.factory import proxy_from_config
-from juju.errors import JujuConnectionError, JujuError, PylibjujuProgrammingError
-from juju.client import client
+from juju.errors import (JujuConnectionError, JujuError,
+                         PylibjujuProgrammingError)
 from juju.version import SUPPORTED_MAJOR_VERSION, TARGET_JUJU_VERSION
 
 log = logging.getLogger('connector')
@@ -113,8 +115,6 @@ async def connect_controller(self, controller_name=None, specified_facades=None)
         """
         if not controller_name:
             controller_name = self.jujudata.current_controller()
-        if not controller_name:
-            raise JujuConnectionError('No current controller. Is Juju bootstrapped?')
 
         controller = self.jujudata.controllers()[controller_name]
         endpoints = controller[API_ENDPOINTS_KEY]
diff --git a/juju/client/jujudata.py b/juju/client/jujudata.py
index ef46f15b..ee0c3bbc 100644
--- a/juju/client/jujudata.py
+++ b/juju/client/jujudata.py
@@ -6,11 +6,13 @@
 import os
 import pathlib
 
-from juju.client import client as jujuclient
 import yaml
+
 from juju import tag
+from juju.client import client as jujuclient
 from juju.client.gocookies import GoCookieJar
-from juju.errors import JujuError, PylibjujuProgrammingError
+from juju.errors import (JujuControllerNotFoundError, JujuError,
+                         PylibjujuProgrammingError)
 from juju.utils import juju_config_dir
 
 API_ENDPOINTS_KEY = 'api-endpoints'
@@ -80,7 +82,7 @@ def current_controller(self):
         try:
             return self._load_yaml('controllers.yaml', 'current-controller')
         except FileNotFoundError:
-            return None
+            raise JujuControllerNotFoundError('No controllers.yaml file found. Did you forget to bootstrap Juju?')
 
     def current_model(self, controller_name=None, model_only=False):
         '''Return the current model, qualified by its controller name.
diff --git a/juju/errors.py b/juju/errors.py
index 2232420c..b108442e 100644
--- a/juju/errors.py
+++ b/juju/errors.py
@@ -123,6 +123,10 @@ class JujuModelConfigError(JujuConfigError):
     pass
 
 
+class JujuControllerNotFoundError(JujuError):
+    pass
+
+
 class AbstractMethodError(Exception):
     pass
 
diff --git a/tests/unit/test_jujudata.py b/tests/unit/test_jujudata.py
index 2684b96d..5d7e7312 100644
--- a/tests/unit/test_jujudata.py
+++ b/tests/unit/test_jujudata.py
@@ -4,8 +4,10 @@
 import unittest
 
 import mock
+import pytest
 
 from juju.client.jujudata import FileJujuData
+from juju.errors import JujuControllerNotFoundError
 
 
 class TestJujuData(unittest.IsolatedAsyncioTestCase):
@@ -13,4 +15,5 @@ class TestJujuData(unittest.IsolatedAsyncioTestCase):
     async def test_verify_controller_uninitialized(self, mock_io_open):
         mock_io_open.side_effect = FileNotFoundError()
         jujudata = FileJujuData()
-        assert jujudata.current_controller() is None
+        with pytest.raises(JujuControllerNotFoundError):
+            jujudata.current_controller()