diff --git a/src/calibre/db/adding.py b/src/calibre/db/adding.py
index 8059afcf3a..a1b5e25850 100644
--- a/src/calibre/db/adding.py
+++ b/src/calibre/db/adding.py
@@ -5,15 +5,18 @@
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import os, time, re
+import os
+import re
+import time
 from collections import defaultdict
-from polyglot.builtins import itervalues, map as it_map, unicode_type
 from contextlib import contextmanager
 from functools import partial
 
 from calibre import prints
-from calibre.constants import iswindows, ismacos, filesystem_encoding
+from calibre.constants import filesystem_encoding, ismacos, iswindows
 from calibre.ebooks import BOOK_EXTENSIONS
+from calibre.utils.filenames import make_long_path_useable
+from polyglot.builtins import itervalues, map as it_map, unicode_type
 
 
 def splitext(path):
@@ -85,7 +88,7 @@ else:
 
 
 def listdir(root, sort_by_mtime=False):
-    items = (os.path.join(root, x) for x in unicode_listdir(root))
+    items = (make_long_path_useable(os.path.join(root, x)) for x in unicode_listdir(root))
     if sort_by_mtime:
         def safe_mtime(x):
             try:
@@ -123,12 +126,13 @@ def run_import_plugins(formats):
     ans = run_import_plugins(formats, import_ctx['group_id'], import_ctx['tdir'])
     fm = import_ctx['format_map']
     for old_path, new_path in zip(formats, ans):
+        new_path = make_long_path_useable(new_path)
         fm[new_path] = old_path
     return ans
 
 
 def find_books_in_directory(dirpath, single_book_per_directory, compiled_rules=(), listdir_impl=listdir):
-    dirpath = os.path.abspath(dirpath)
+    dirpath = make_long_path_useable(os.path.abspath(dirpath))
     if single_book_per_directory:
         formats = {}
         for path in listdir_impl(dirpath):