diff --git a/src/tree/TreeBuilder.java b/src/tree/TreeBuilder.java
index 51c4471ee7..d8f20a2d55 100644
--- a/src/tree/TreeBuilder.java
+++ b/src/tree/TreeBuilder.java
@@ -510,7 +510,9 @@ public List<Tree> call(final List<Tree> loaded_trees)
           local_trees = new ArrayList<Tree>(trees.size());
           local_trees.addAll(trees);
         }
-        
+
+        trees_lock.unlock();
+
         return local_trees;
       }
       
@@ -547,6 +549,8 @@ public Object call(final Exception e) throws Exception {
     final List<Tree> local_trees;
     if (trees.isEmpty()) {
       LOG.debug("No trees were found to process the meta through");
+      trees_lock.unlock();
+
       return Deferred.fromResult(true);
     }