diff --git a/src/calibre/ptempfile.py b/src/calibre/ptempfile.py
index 16a1ef4ce4..0aa71770a0 100644
--- a/src/calibre/ptempfile.py
+++ b/src/calibre/ptempfile.py
@@ -7,7 +7,8 @@ being closed.
 """
 import tempfile, os, atexit, binascii, cPickle
 
-from calibre import __version__, __appname__
+from calibre import __version__, __appname__, isbytestring
+from calibre.constants import filesystem_encoding
 
 def cleanup(path):
     try:
@@ -42,6 +43,8 @@ def base_dir():
             _base_dir = tempfile.mkdtemp(prefix='%s_%s_tmp_'%(__appname__,
                 __version__))
             atexit.register(remove_dir, _base_dir)
+    if isbytestring(_base_dir):
+        _base_dir = _base_dir.decode(filesystem_encoding)
     return _base_dir
 
 class PersistentTemporaryFile(object):