diff --git a/Lib/multiprocessing/synchronize.py b/Lib/multiprocessing/synchronize.py
index 428656a..dacf45a 100644
--- a/Lib/multiprocessing/synchronize.py
+++ b/Lib/multiprocessing/synchronize.py
@@ -21,6 +21,17 @@
 from multiprocessing.util import Finalize, register_after_fork, debug
 from multiprocessing.forking import assert_spawning, Popen
 
+# Try to import the mp.synchronize module cleanly, if it fails
+# raise ImportError for platforms lacking a working sem_open implementation.
+# See issue 3770
+try:
+    from _multiprocessing import SemLock
+except (ImportError):
+    raise ImportError("This platform lacks a functioning sem_open" +
+                      " implementation, therefore, the required" +
+                      " synchronization primitives needed will not" +
+                      " function, see issue 3770.")
+
 #
 # Constants
 #
diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index f185111..996395b 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -1047,6 +1047,7 @@
         test_tcl
         test_timeout
         test_urllibnet
+        test_multiprocessing
         """,
     'aix5':
         """
@@ -1077,6 +1078,7 @@
         test_ossaudiodev
         test_pep277
         test_tcl
+        test_multiprocessing
         """,
     'netbsd3':
         """
@@ -1092,6 +1094,7 @@
         test_ossaudiodev
         test_pep277
         test_tcl
+        test_multiprocessing
         """,
 }
 _expectations['freebsd5'] = _expectations['freebsd4']
diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py
index 214a420..b0746e9 100644
--- a/Lib/test/test_multiprocessing.py
+++ b/Lib/test/test_multiprocessing.py
@@ -18,6 +18,14 @@
 import random
 import logging
 
+
+# Work around broken sem_open implementations
+try:
+    import multiprocessing.synchronize
+except ImportError, e:
+    from test.test_support import TestSkipped
+    raise TestSkipped(e)
+
 import multiprocessing.dummy
 import multiprocessing.connection
 import multiprocessing.managers