diff -r 10b1f60a72fa Lib/mimetypes.py
--- a/Lib/mimetypes.py	Sun Feb 23 19:41:51 2014 +0100
+++ b/Lib/mimetypes.py	Mon Feb 24 17:18:07 2014 +1100
@@ -252,10 +252,10 @@
         with _winreg.OpenKey(_winreg.HKEY_CLASSES_ROOT, '') as hkcr:
             for subkeyname in enum_types(hkcr):
                 try:
+                    # Only check file extensions
+                    if not subkeyname.startswith("."):
+                        continue
                     with _winreg.OpenKey(hkcr, subkeyname) as subkey:
-                        # Only check file extensions
-                        if not subkeyname.startswith("."):
-                            continue
                         # raises EnvironmentError if no 'Content Type' value
                         mimetype, datatype = _winreg.QueryValueEx(
                             subkey, 'Content Type')