diff --git a/chainsyncer/store/fs.py b/chainsyncer/store/fs.py
index c70889c..88b1f5c 100644
--- a/chainsyncer/store/fs.py
+++ b/chainsyncer/store/fs.py
@@ -77,6 +77,8 @@ class SyncFsItem:
         
     def next(self, advance_block=False):
         v = self.sync_state.get(self.state_key)
+        if v == self.sync_state.DONE:
+            raise SyncDone(self.target)
 
         (block_number, tx_index, target) = sync_state_deserialize(v)
         if advance_block: