diff --git a/src/dexorder/blockstate/state.py b/src/dexorder/blockstate/state.py
index 43123fe..9ed60e2 100644
--- a/src/dexorder/blockstate/state.py
+++ b/src/dexorder/blockstate/state.py
@@ -93,6 +93,9 @@ class BlockState:
 
 
     def fork(self, block: Block):
+        if block.hash == self.root_block.hash:
+            return Fork([block.hash], height=block.height)
+
         if block.height - self.ancestors[block.hash].height > 1:
             # noinspection PyTypeChecker
             return DisjointFork(block, self.root_block)