diff --git a/mopidy/backends/base.py b/mopidy/backends/base.py
index c45eb771..9f531450 100644
--- a/mopidy/backends/base.py
+++ b/mopidy/backends/base.py
@@ -15,6 +15,11 @@ class Backend(object):
     #: the backend doesn't provide a library.
     library = None
 
+    #: The library update provider. An instance of
+    #: :class:`~mopidy.backends.base.BaseLibraryUpdateProvider`, or
+    #: :class:`None` if the backend doesn't provide a library.
+    updater = None
+
     #: The playback provider. An instance of
     #: :class:`~mopidy.backends.base.BasePlaybackProvider`, or :class:`None` if
     #: the backend doesn't provide playback.
@@ -35,6 +40,9 @@ class Backend(object):
     def has_library(self):
         return self.library is not None
 
+    def has_updater(self):
+        return self.updater is not None
+
     def has_playback(self):
         return self.playback is not None
 
@@ -53,6 +61,7 @@ class BaseLibraryProvider(object):
     def __init__(self, backend):
         self.backend = backend
 
+    # TODO: replace with search(query, exact=Ture, ...)
     def find_exact(self, query=None, uris=None):
         """
         See :meth:`mopidy.core.LibraryController.find_exact`.
@@ -86,6 +95,48 @@ class BaseLibraryProvider(object):
         pass
 
 
+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
+
+    def load(self):
+        """Loads the library and returns all tracks in it.
+
+        *MUST be implemented by subclass.*
+        """
+        raise NotImplementedError
+
+    def add(self, track):
+        """Adds given track to library.
+
+        Overwrites any existing entry with same uri.
+
+        *MUST be implemented by subclass.*
+        """
+        raise NotImplementedError
+
+    def remove(self, uri):
+        """Removes given track from library.
+
+        *MUST be implemented by subclass.*
+        """
+        raise NotImplementedError
+
+    def commit(self):
+        """Persist changes to library.
+
+        *MAY be implemented by subclass.*
+        """
+        pass
+
+
 class BasePlaybackProvider(object):
     """
     :param audio: the audio actor
diff --git a/mopidy/scanner.py b/mopidy/scanner.py
index 0cc51d2a..ba8f2ff9 100644
--- a/mopidy/scanner.py
+++ b/mopidy/scanner.py
@@ -111,15 +111,19 @@ def main():
     tmp = tempfile.NamedTemporaryFile(
         prefix=basename + '.', dir=directory, delete=False)
 
-    for row in mpd_translator.tracks_to_tag_cache_format(
-            tracks.values(), config['local']['media_dir']):
-        if len(row) == 1:
-            tmp.write(('%s\n' % row).encode('utf-8'))
-        else:
-            tmp.write(('%s: %s\n' % row).encode('utf-8'))
+    try:
+        for row in mpd_translator.tracks_to_tag_cache_format(
+                tracks.values(), config['local']['media_dir']):
+            if len(row) == 1:
+                tmp.write(('%s\n' % row).encode('utf-8'))
+            else:
+                tmp.write(('%s: %s\n' % row).encode('utf-8'))
 
-    os.rename(tmp.name, config['local']['tag_cache_file'])
-    logging.info('Done writing; overwriting active tag cache.')
+        logging.info('Done writing; overwriting active tag cache.')
+        os.rename(tmp.name, config['local']['tag_cache_file'])
+    finally:
+        if os.path.exists(tmp.name):
+            os.remove(tmp.name)
 
 
 def parse_args():