diff --git a/src/ZEO/ClientStorage.py b/src/ZEO/ClientStorage.py
index 9dd977be69d3b1bbeedbdb11aca3bccb8be3668c..94ec7cc7beef29fb31b18ea4885e836e2dfc8ade 100644
--- a/src/ZEO/ClientStorage.py
+++ b/src/ZEO/ClientStorage.py
@@ -266,9 +266,7 @@ class ClientStorage:
 
     def close(self):
         """Storage API: finalize the storage, releasing external resources."""
-        if self._tbuf is not None:
-            self._tbuf.close()
-            self._tbuf = None
+        self._tbuf.close()
         if self._cache is not None:
             self._cache.close()
             self._cache = None