diff --git a/src/calibre/gui2/tweak_book/spell.py b/src/calibre/gui2/tweak_book/spell.py
index c992b81035..7a8a52b4df 100644
--- a/src/calibre/gui2/tweak_book/spell.py
+++ b/src/calibre/gui2/tweak_book/spell.py
@@ -19,7 +19,7 @@ from calibre.gui2 import choose_files, error_dialog
 from calibre.gui2.tweak_book.widgets import Dialog
 from calibre.spell.dictionary import (
     builtin_dictionaries, custom_dictionaries, best_locale_for_language,
-    get_dictionary, DictionaryLocale, dprefs, remove_dictionary)
+    get_dictionary, DictionaryLocale, dprefs, remove_dictionary, rename_dictionary)
 from calibre.spell.import_from import import_from_oxt
 from calibre.utils.localization import calibre_langcode_to_name
 from calibre.utils.icu import sort_key
@@ -103,8 +103,10 @@ class AddDictionary(QDialog):  # {{{
         try:
             num = import_from_oxt(oxt, nick)
         except:
+            import traceback
             return error_dialog(self, _('Failed to import dictionaries'), _(
-                'Failed to import dictionaries from %s. Click "Show Details" for more information') % oxt, show=True)
+                'Failed to import dictionaries from %s. Click "Show Details" for more information') % oxt,
+                                det_msg=traceback.format_exc(), show=True)
         if num == 0:
             return error_dialog(self, _('No dictionaries'), _(
                 'No dictionaries were found in %s') % oxt, show=True)
@@ -146,6 +148,7 @@ class ManageDictionaries(Dialog):
         s.addWidget(w)
 
         self.dictionaries = d = QTreeWidget(self)
+        d.itemChanged.connect(self.data_changed, type=Qt.QueuedConnection)
         self.build_dictionaries()
         d.setCurrentIndex(d.model().index(0, 0))
         d.header().close()
@@ -161,6 +164,12 @@ class ManageDictionaries(Dialog):
         b.clicked.connect(self.add_dictionary)
         l.addWidget(self.bb, l.rowCount(), 0, 1, l.columnCount())
 
+    def data_changed(self, item, column):
+        if column == 0 and item.type() == DICTIONARY:
+            d = item.data(0, Qt.UserRole).toPyObject()
+            if not d.builtin and unicode(item.text(0)) != d.name:
+                rename_dictionary(d, unicode(item.text(0)))
+
     def build_dictionaries(self, reread=False):
         all_dictionaries = builtin_dictionaries() | custom_dictionaries(reread=reread)
         languages = defaultdict(lambda : defaultdict(set))
@@ -192,6 +201,8 @@ class ManageDictionaries(Dialog):
                         pl += '-' + dictionary.primary_locale.countrycode.upper()
                     k.setText(0, dictionary.name or (_('<Builtin dictionary for {0}>').format(pl)))
                     k.setData(0, Qt.UserRole, dictionary)
+                    if dictionary.name:
+                        k.setFlags(k.flags() | Qt.ItemIsEditable)
                     if pd == dictionary:
                         k.setData(0, Qt.FontRole, itf)
 
diff --git a/src/calibre/spell/dictionary.py b/src/calibre/spell/dictionary.py
index 677f4cc186..fd5939c58e 100644
--- a/src/calibre/spell/dictionary.py
+++ b/src/calibre/spell/dictionary.py
@@ -70,7 +70,10 @@ def custom_dictionaries(reread=False):
         dics = []
         for lc in glob.glob(os.path.join(config_dir, 'dictionaries', '*/locales')):
             locales = filter(None, open(lc, 'rb').read().decode('utf-8').splitlines())
-            name, locale, locales = locales[0], locales[1], locales[1:]
+            try:
+                name, locale, locales = locales[0], locales[1], locales[1:]
+            except IndexError:
+                continue
             base = os.path.dirname(lc)
             dics.append(Dictionary(
                 parse_lang_code(locale), frozenset(map(parse_lang_code, locales)), os.path.join(base, '%s.dic' % locale),
@@ -95,6 +98,14 @@ def remove_dictionary(dictionary):
     shutil.rmtree(base)
     dprefs['preferred_dictionaries'] = {k:v for k, v in dprefs['preferred_dictionaries'].iteritems() if v != dictionary.id}
 
+def rename_dictionary(dictionary, name):
+    lf = os.path.join(os.path.dirname(dictionary.dicpath), 'locales')
+    with open(lf, 'r+b') as f:
+        lines = f.read().splitlines()
+        lines[:1] = [name.encode('utf-8')]
+        f.seek(0), f.truncate(), f.write(b'\n'.join(lines))
+    custom_dictionaries(reread=True)
+
 def get_dictionary(locale, exact_match=False):
     preferred = preferred_dictionary(locale)
     # First find all dictionaries that match locale exactly
diff --git a/src/calibre/spell/import_from.py b/src/calibre/spell/import_from.py
index bda9155dd3..a83c92e345 100644
--- a/src/calibre/spell/import_from.py
+++ b/src/calibre/spell/import_from.py
@@ -63,6 +63,8 @@ def import_from_libreoffice_source_tree(source_path):
 
 def import_from_oxt(source_path, name, dest_dir=None, prefix='dic-'):
     dest_dir = dest_dir or os.path.join(config_dir, 'dictionaries')
+    if not os.path.exists(dest_dir):
+        os.makedirs(dest_dir)
     num = 0
     with ZipFile(source_path) as zf:
         root = etree.fromstring(zf.open('META-INF/manifest.xml').read())