diff --git a/Lib/mailbox.py b/Lib/mailbox.py
index d054628..b72128b 100755
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -15,6 +15,9 @@
 import rfc822
 import StringIO
 try:
+    if sys.platform == 'os2emx':
+        # OS/2 EMX fcntl() not adequate
+        raise ImportError
     import fcntl
 except ImportError:
     fcntl = None
@@ -565,7 +568,8 @@
         try:
             os.rename(new_file.name, self._path)
         except OSError, e:
-            if e.errno == errno.EEXIST:
+            if e.errno == errno.EEXIST or \
+              (os.name == 'os2' and e.errno == errno.EACCES):
                 os.remove(self._path)
                 os.rename(new_file.name, self._path)
             else:
@@ -1030,6 +1034,9 @@
                         if hasattr(os, 'link'):
                             os.link(os.path.join(self._path, str(key)),
                                     os.path.join(self._path, str(prev + 1)))
+                            if sys.platform == 'os2emx':
+                                # cannot unlink an open file on OS/2
+                                f.close()
                             os.unlink(os.path.join(self._path, str(key)))
                         else:
                             f.close()
@@ -1828,7 +1835,8 @@
                     os.rename(pre_lock.name, f.name + '.lock')
                     dotlock_done = True
             except OSError, e:
-                if e.errno == errno.EEXIST:
+                if e.errno == errno.EEXIST or \
+                  (os.name == 'os2' and e.errno == errno.EACCES):
                     os.remove(pre_lock.name)
                     raise ExternalClashError('dot lock unavailable: %s' %
                                              f.name)
diff --git a/Lib/test/test_mailbox.py b/Lib/test/test_mailbox.py
index 2f8cb8d..45dd118 100644
--- a/Lib/test/test_mailbox.py
+++ b/Lib/test/test_mailbox.py
@@ -461,7 +461,7 @@
 
     def setUp(self):
         TestMailbox.setUp(self)
-        if os.name == 'nt':
+        if os.name in ('nt', 'os2'):
             self._box.colon = '!'
 
     def test_add_MM(self):
@@ -520,7 +520,7 @@
         # Initialize an existing mailbox
         self.tearDown()
         for subdir in '', 'tmp', 'new', 'cur':
-            os.mkdir(os.path.join(self._path, subdir))
+            os.mkdir(os.path.normpath(os.path.join(self._path, subdir)))
         self._box = mailbox.Maildir(self._path)
         self._check_basics(factory=rfc822.Message)
         self._box = mailbox.Maildir(self._path, factory=None)