diff --git a/mopidy/backends/base.py b/mopidy/backends/base.py
index f0561b4c..292fa4cb 100644
--- a/mopidy/backends/base.py
+++ b/mopidy/backends/base.py
@@ -96,15 +96,7 @@ class BaseLibraryProvider(object):
 
 
 class BaseLibraryUpdateProvider(object):
-    """
-    :param backend: backend the controller is a part of
-    :type backend: :class:`mopidy.backends.base.Backend`
-    """
-
-    pykka_traversable = True
-
-    def __init__(self, backend):
-        self.backend = backend
+    uri_schemes = []
 
     def load(self):
         """Loads the library and returns all tracks in it.
diff --git a/mopidy/backends/local/actor.py b/mopidy/backends/local/actor.py
index b73c53e2..8f53af4d 100644
--- a/mopidy/backends/local/actor.py
+++ b/mopidy/backends/local/actor.py
@@ -8,7 +8,7 @@ import pykka
 from mopidy.backends import base
 from mopidy.utils import encoding, path
 
-from .library import LocalLibraryProvider, LocalLibraryUpdateProvider
+from .library import LocalLibraryProvider
 from .playlists import LocalPlaylistsProvider
 
 logger = logging.getLogger('mopidy.backends.local')
@@ -23,7 +23,6 @@ class LocalBackend(pykka.ThreadingActor, base.Backend):
         self.check_dirs_and_files()
 
         self.library = LocalLibraryProvider(backend=self)
-        self.updater = LocalLibraryUpdateProvider(backend=self)
         self.playback = base.BasePlaybackProvider(audio=audio, backend=self)
         self.playlists = LocalPlaylistsProvider(backend=self)
 
diff --git a/mopidy/backends/local/library.py b/mopidy/backends/local/library.py
index 43768cd4..c80e95fe 100644
--- a/mopidy/backends/local/library.py
+++ b/mopidy/backends/local/library.py
@@ -135,11 +135,12 @@ class LocalLibraryProvider(base.BaseLibraryProvider):
 
 # TODO: rename and move to tagcache extension.
 class LocalLibraryUpdateProvider(base.BaseLibraryProvider):
-    def __init__(self, *args, **kwargs):
-        super(LocalLibraryUpdateProvider, self).__init__(*args, **kwargs)
+    uri_schemes = ['file']
+
+    def __init__(self, config):
         self._tracks = {}
-        self._media_dir = self.backend.config['local']['media_dir']
-        self._tag_cache_file = self.backend.config['local']['tag_cache_file']
+        self._media_dir = config['local']['media_dir']
+        self._tag_cache_file = config['local']['tag_cache_file']
 
     def load(self):
         tracks = parse_mpd_tag_cache(self._tag_cache_file, self._media_dir)
@@ -156,6 +157,8 @@ class LocalLibraryUpdateProvider(base.BaseLibraryProvider):
 
     def commit(self):
         directory, basename = os.path.split(self._tag_cache_file)
+
+        # TODO: cleanup directory/basename.* files.
         tmp = tempfile.NamedTemporaryFile(
             prefix=basename + '.', dir=directory, delete=False)
 
diff --git a/mopidy/scanner.py b/mopidy/scanner.py
index 9f13d454..2a901910 100644
--- a/mopidy/scanner.py
+++ b/mopidy/scanner.py
@@ -45,9 +45,9 @@ def main():
     log.setup_root_logger()
     log.setup_console_logging(logging_config, args.verbosity_level)
 
-    extensions = dict((e.ext_name, e) for e in ext.load_extensions())
+    extensions = ext.load_extensions()
     config, errors = config_lib.load(
-        config_files, extensions.values(), config_overrides)
+        config_files, extensions, config_overrides)
     log.setup_log_levels(config)
 
     if not config['local']['media_dir']:
@@ -56,10 +56,21 @@ def main():
 
     # TODO: missing config error checking and other default setup code.
 
-    audio = dummy_audio.DummyAudio()
-    local_backend_classes = extensions['local'].get_backend_classes()
-    local_backend = local_backend_classes[0](config, audio)
-    local_updater = local_backend.updater
+    updaters = {}
+    for e in extensions:
+        for updater_class in e.get_library_updaters():
+            if updater_class and 'file' in updater_class.uri_schemes:
+                updaters[e.ext_name] = updater_class
+
+    if not updaters:
+        logging.error('No usable updaters found.')
+        return
+    elif len(updaters) > 1:
+        names = ', '.join(updaters.keys())
+        logging.error('More than one updater found. Provided by: %s', names)
+        return
+
+    local_updater = updaters.values()[0](config)  # TODO: switch to actor?
 
     media_dir = config['local']['media_dir']