Index: Lib/mailbox.py
===================================================================
--- Lib/mailbox.py	(révision 76002)
+++ Lib/mailbox.py	(copie de travail)
@@ -458,11 +458,17 @@
 
     def _refresh(self):
         """Update table of contents mapping."""
-        new_mtime = os.path.getmtime(os.path.join(self._path, 'new'))
-        cur_mtime = os.path.getmtime(os.path.join(self._path, 'cur'))
-
-        if (self._last_read is not None and
-            new_mtime <= self._last_read and cur_mtime <= self._last_read):
+        for subdir in ('new', 'cur'):
+            path = os.path.join(self._path, subdir)
+            fd = os.open(path, os.O_RDONLY)
+            try:
+                os.fsync(fd)
+            finally:
+                os.close(fd)
+            mtime = os.path.getmtime(path)
+            if self._last_read is None or mtime >= self._last_read:
+                break
+        else:
             return
 
         self._toc = {}