diff --git a/src/calibre/gui2/qt_file_dialogs.py b/src/calibre/gui2/qt_file_dialogs.py
index b1f2114b16..4740cc1a06 100644
--- a/src/calibre/gui2/qt_file_dialogs.py
+++ b/src/calibre/gui2/qt_file_dialogs.py
@@ -9,7 +9,6 @@ import os
 from PyQt5.Qt import QFileDialog, QObject
 
 from calibre.gui2.linux_file_dialogs import dialog_name, image_extensions
-from calibre.utils.filenames import expanduser
 from polyglot.builtins import unicode_type, string_or_bytes
 from polyglot.urllib import unquote
 
@@ -22,7 +21,7 @@ def select_initial_dir(q):
         if os.path.exists(c):
             return c
         q = c
-    return expanduser(u'~')
+    return os.path.expanduser(u'~')
 
 
 class FileDialog(QObject):
@@ -59,20 +58,20 @@ class FileDialog(QObject):
         if combine_file_and_saved_dir:
             bn = os.path.basename(default_dir)
             prev = dynamic.get(self.dialog_name,
-                    expanduser(u'~'))
+                    os.path.expanduser(u'~'))
             if os.path.exists(prev):
                 if os.path.isfile(prev):
                     prev = os.path.dirname(prev)
             else:
-                prev = expanduser(u'~')
+                prev = os.path.expanduser(u'~')
             initial_dir = os.path.join(prev, bn)
         elif no_save_dir:
-            initial_dir = expanduser(default_dir)
+            initial_dir = os.path.expanduser(default_dir)
         else:
             initial_dir = dynamic.get(self.dialog_name,
-                    expanduser(default_dir))
+                    os.path.expanduser(default_dir))
         if not isinstance(initial_dir, string_or_bytes):
-            initial_dir = expanduser(default_dir)
+            initial_dir = os.path.expanduser(default_dir)
         if not initial_dir or (not os.path.exists(initial_dir) and not (
                 mode == QFileDialog.AnyFile and (no_save_dir or combine_file_and_saved_dir))):
             initial_dir = select_initial_dir(initial_dir)
diff --git a/src/calibre/gui2/viewer/printing.py b/src/calibre/gui2/viewer/printing.py
index c354fc6a35..ec5f78f443 100644
--- a/src/calibre/gui2/viewer/printing.py
+++ b/src/calibre/gui2/viewer/printing.py
@@ -20,7 +20,6 @@ from calibre.gui2.widgets2 import Dialog
 from calibre.gui2.viewer.main import vprefs
 from calibre.utils.icu import numeric_sort_key
 from calibre.utils.ipc.simple_worker import start_pipe_worker
-from calibre.utils.filenames import expanduser
 from calibre.utils.serialize import msgpack_dumps, msgpack_loads
 
 
@@ -41,7 +40,7 @@ class PrintDialog(Dialog):
         self.file_name = f = QLineEdit(self)
         val = dynamic.get(self.OUTPUT_NAME, None)
         if not val:
-            val = expanduser('~')
+            val = os.path.expanduser('~')
         else:
             val = os.path.dirname(val)
         f.setText(os.path.abspath(os.path.join(val, self.default_file_name)))
diff --git a/src/calibre/gui2/win_file_dialogs.py b/src/calibre/gui2/win_file_dialogs.py
index 97b5cb54bf..b4e93a7331 100644
--- a/src/calibre/gui2/win_file_dialogs.py
+++ b/src/calibre/gui2/win_file_dialogs.py
@@ -27,11 +27,9 @@ def is_ok():
 
 try:
     from calibre.constants import filesystem_encoding
-    from calibre.utils.filenames import expanduser
     from calibre.utils.config import dynamic
 except ImportError:
-    filesystem_encoding = 'utf-8'
-    expanduser = os.path.expanduser
+    filesystem_encoding = 'mbcs'
     dynamic = {}
 
 
@@ -111,7 +109,7 @@ class Loop(QEventLoop):
 def process_path(x):
     if isinstance(x, bytes):
         x = x.decode(filesystem_encoding)
-    return os.path.abspath(expanduser(x))
+    return os.path.abspath(os.path.expanduser(x))
 
 
 def select_initial_dir(q):
@@ -122,7 +120,7 @@ def select_initial_dir(q):
         if os.path.exists(c):
             return c
         q = c
-    return expanduser('~')
+    return os.path.expanduser('~')
 
 
 def run_file_dialog(
@@ -225,9 +223,9 @@ def run_file_dialog(
 def get_initial_folder(name, title, default_dir='~', no_save_dir=False):
     name = name or 'dialog_' + title
     if no_save_dir:
-        initial_folder = expanduser(default_dir)
+        initial_folder = os.path.expanduser(default_dir)
     else:
-        initial_folder = dynamic.get(name, expanduser(default_dir))
+        initial_folder = dynamic.get(name, os.path.expanduser(default_dir))
     if not initial_folder or not os.path.isdir(initial_folder):
         initial_folder = select_initial_dir(initial_folder)
     return name, initial_folder
diff --git a/src/calibre/library/__init__.py b/src/calibre/library/__init__.py
index 4e05cc537f..316961fb21 100644
--- a/src/calibre/library/__init__.py
+++ b/src/calibre/library/__init__.py
@@ -4,14 +4,14 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 ''' Code to manage ebook library'''
 
 
+import os
 from polyglot.builtins import range
 
 
 def db(path=None, read_only=False):
     from calibre.db.legacy import LibraryDatabase
     from calibre.utils.config import prefs
-    from calibre.utils.filenames import expanduser
-    return LibraryDatabase(expanduser(path) if path else prefs['library_path'],
+    return LibraryDatabase(os.path.expanduser(path) if path else prefs['library_path'],
             read_only=read_only)