diff --git a/chunk.py b/chunk.py
index 1749ad6..a5d2969 100644
--- a/chunk.py
+++ b/chunk.py
@@ -366,7 +366,7 @@ class ChunkRenderer(object):
             self._up_right_skylight = get_skylight_array(chunk_data)
             self._up_right_blocklight = get_blocklight_array(chunk_data)
             self._up_right_blocks = get_blockarray(chunk_data)
-        except IOError:
+        except NoSuchChunk:
             self._up_right_skylight = None
             self._up_right_blocklight = None
             self._up_right_blocks = None
@@ -386,7 +386,7 @@ class ChunkRenderer(object):
             self._up_left_skylight = get_skylight_array(chunk_data)
             self._up_left_blocklight = get_blocklight_array(chunk_data)
             self._up_left_blocks = get_blockarray(chunk_data)
-        except IOError:
+        except NoSuchChunk:
             self._up_left_skylight = None
             self._up_left_blocklight = None
             self._up_left_blocks = None
diff --git a/world.py b/world.py
index 8976d15..68a1cec 100644
--- a/world.py
+++ b/world.py
@@ -379,8 +379,7 @@ class WorldRenderer(object):
                     result = pool.apply_async(chunk.render_and_save,
                             args=(chunkXY,self.cachedir,self, oldimg),
                             kwds=dict(cave=self.caves, queue=q))
-                if result:
-                    asyncresults.append((col, row, result))
+                asyncresults.append((col, row, result))
 
             pool.close()