diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index 6ee9923..2aa4bff 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -198,7 +198,10 @@
     # Check to see if this is ZIP file with no archive comment (the
     # "end of central directory" structure should be the last item in the
     # file if this is the case).
-    fpin.seek(-sizeEndCentDir, 2)
+    try:
+        fpin.seek(-sizeEndCentDir, 2)
+    except IOError:
+        return None
     data = fpin.read()
     if data[0:4] == stringEndArchive and data[-2:] == "\000\000":
         # the signature is correct and there's no comment, unpack structure