diff --git a/src/calibre/srv/http_response.py b/src/calibre/srv/http_response.py
index deade8c635..c048c3656f 100644
--- a/src/calibre/srv/http_response.py
+++ b/src/calibre/srv/http_response.py
@@ -6,7 +6,7 @@ from __future__ import (unicode_literals, division, absolute_import,
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, httplib, hashlib, uuid, struct, repr as reprlib, time
+import os, httplib, hashlib, uuid, struct, repr as reprlib
 from collections import namedtuple
 from io import BytesIO, DEFAULT_BUFFER_SIZE
 from itertools import chain, repeat, izip_longest
@@ -22,7 +22,7 @@ from calibre.srv.http_request import HTTPRequest, read_headers
 from calibre.srv.sendfile import file_metadata, sendfile_to_socket_async, CannotSendfile, SendfileInterrupted
 from calibre.srv.utils import (
     MultiDict, http_date, HTTP1, HTTP11, socket_errors_socket_closed,
-    sort_q_values, get_translator_for_lang, Cookie)
+    sort_q_values, get_translator_for_lang, Cookie, fast_now_strftime)
 from calibre.utils.speedups import ReadOnlyFileBuffer
 from calibre.utils.monotonic import monotonic
 
@@ -526,7 +526,7 @@ class HTTPConnection(HTTPRequest):
             return
         line = '%s port-%s %s %s "%s" %s %s' % (
             self.remote_addr, self.remote_port, username or '-',
-            time.strftime('%d/%b/%Y:%H:%M:%S %z'),
+            fast_now_strftime('%d/%b/%Y:%H:%M:%S %z'),
             force_unicode(self.request_line or '', 'utf-8'),
             status_code, ('-' if response_size is None else response_size))
         self.access_log(line)
diff --git a/src/calibre/srv/utils.py b/src/calibre/srv/utils.py
index dc061467be..9b5582bd6a 100644
--- a/src/calibre/srv/utils.py
+++ b/src/calibre/srv/utils.py
@@ -6,7 +6,7 @@ from __future__ import (unicode_literals, division, absolute_import,
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import errno, socket, select, os
+import errno, socket, select, os, time
 from Cookie import SimpleCookie
 from contextlib import closing
 from urlparse import parse_qs
@@ -508,3 +508,12 @@ def get_use_roman():
         from calibre.gui2 import config
         _use_roman = config['use_roman_numerals_for_series_number']
     return _use_roman
+
+
+if iswindows:
+    def fast_now_strftime(fmt):
+        fmt = fmt.encode('mbcs')
+        return time.strftime(fmt).decode('mbcs', 'replace')
+else:
+    def fast_now_strftime(fmt):
+        return time.strftime(fmt).decode('utf-8', 'replace')