diff --git a/setup/installer/osx/app/site.py b/setup/installer/osx/app/site.py
index 5232706727..a0b408f728 100644
--- a/setup/installer/osx/app/site.py
+++ b/setup/installer/osx/app/site.py
@@ -80,7 +80,7 @@ def addpackage(sitedir, name):
         f = open(fullname)
     except IOError:
         return
-    while 1:
+    while True:
         dir = f.readline()
         if not dir:
             break
@@ -99,14 +99,12 @@ def addpackage(sitedir, name):
         _dirs_in_sys_path = None
 
 
-sys.setdefaultencoding('utf-8')
-
-#
 # Remove sys.setdefaultencoding() so that users cannot change the
 # encoding after initialization.  The test for presence is needed when
 # this module is run as a script, because this code is executed twice.
 #
 if hasattr(sys, "setdefaultencoding"):
+    sys.setdefaultencoding('utf-8')
     del sys.setdefaultencoding
 
 def run_entry_point():
@@ -127,6 +125,62 @@ def add_calibre_vars(base):
     if dv and os.path.exists(dv):
         sys.path.insert(0, os.path.abspath(dv))
 
+def setup_asl():
+    # On Mac OS X 10.8 or later the contents of stdout and stderr
+    # do not end up in Console.app
+    # This function detects if "asl_log_descriptor" is available
+    # (introduced in 10.8), and if it is configures ASL to redirect
+    # all writes to stdout/stderr to Console.app
+    import ctypes
+    try:
+        syslib = ctypes.CDLL("/usr/lib/libSystem.dylib")
+    except EnvironmentError:
+        import ctypes.util
+        syslib = ctypes.CDLL(ctypes.util.find_library('System'))
+
+    asl_log_descriptor_proto = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_int, ctypes.c_int, ctypes.c_uint32)
+    try:
+        asl_log_descriptor = asl_log_descriptor_proto(('asl_log_descriptor', syslib), ((1, 'asl'), (1, 'msg'), (1, 'level'), (1, 'descriptor'), (1, 'fd_type')))
+    except AttributeError:
+        # OS X < 10.8 no need to redirect
+        return
+    asl_open_proto = ctypes.CFUNCTYPE(ctypes.c_void_p, ctypes.c_char_p, ctypes.c_char_p, ctypes.c_uint32)
+    asl_open = asl_open_proto(('asl_open', syslib), ((1, "ident"), (1, "facility"), (1, 'opts')))
+    asl_new_proto = ctypes.CFUNCTYPE(ctypes.c_void_p, ctypes.c_uint32)
+    asl_new = asl_new_proto(('asl_new', syslib), ((1, "type"),))
+    asl_set_proto = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_void_p, ctypes.c_char_p, ctypes.c_char_p)
+    asl_set = asl_set_proto(('asl_set', syslib), ((1, "msg"), (1, "key"), (1, "value")))
+
+    CONSOLE = b'com.apple.console'
+    # Taken from asl.h
+    ASL_OPT_NO_DELAY = 2
+    ASL_TYPE_MSG = 0
+    ASL_KEY_FACILITY = b'Facility'
+    ASL_KEY_LEVEL = b'Level'
+    ASL_KEY_READ_UID = b'ReadUID'
+    ASL_STRING_NOTICE = b'Notice'
+    ASL_LEVEL_NOTICE = 4
+    ASL_LOG_DESCRIPTOR_WRITE = 2
+
+    cl = asl_open(ident=getattr(sys, 'calibre_basename', b'calibre'), facility=CONSOLE, opts=ASL_OPT_NO_DELAY)
+    if cl is None:
+        return
+
+    # Create an ASL template message for the STDOUT/STDERR redirection.
+    msg = asl_new(ASL_TYPE_MSG)
+    if msg is None:
+        return
+    if asl_set(msg, ASL_KEY_FACILITY, CONSOLE) != 0:
+        return
+    if asl_set(msg, ASL_KEY_LEVEL, ASL_STRING_NOTICE) != 0:
+        return
+    if asl_set(msg, ASL_KEY_READ_UID, bytes('%d' % os.getuid())) != 0:
+        return
+    # Redirect the STDOUT/STDERR file descriptors to ASL
+    if asl_log_descriptor(cl, msg, ASL_LEVEL_NOTICE, sys.stdout.fileno(), ASL_LOG_DESCRIPTOR_WRITE) != 0:
+        return
+    if asl_log_descriptor(cl, msg, ASL_LEVEL_NOTICE, sys.stderr.fileno(), ASL_LOG_DESCRIPTOR_WRITE) != 0:
+        return
 
 def main():
     global __file__
@@ -139,11 +193,16 @@ def main():
     add_calibre_vars(base)
     addsitedir(sys.site_packages)
 
+    launched_by_launch_services = False
 
-    for arg in list(sys.argv[1:]):
-        if arg.startswith('-psn'):
+    for arg in tuple(sys.argv[1:]):
+        if arg.startswith('-psn_'):
             sys.argv.remove(arg)
+            launched_by_launch_services = True
+    if launched_by_launch_services:
+        try:
+            setup_asl()
+        except:
+            pass  # Failure to log to Console.app is not critical
 
     return run_entry_point()
-
-