diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index e560ac7c6e..ccc5b60427 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -40,7 +40,7 @@ from calibre.ebooks import BOOK_EXTENSIONS, check_ebook_format
 from calibre.utils.magick.draw import save_cover_data_to
 from calibre.utils.recycle_bin import delete_file, delete_tree
 from calibre.utils.formatter_functions import load_user_template_functions
-
+from calibre.utils.config import test_eight_code
 
 copyfile = os.link if hasattr(os, 'link') else shutil.copyfile
 
@@ -214,7 +214,11 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         defs['gui_restriction'] = defs['cs_restriction'] = ''
         defs['categories_using_hierarchy'] = []
         defs['edit_metadata_single_layout'] = 'default'
-        defs['bools_are_tristate'] = tweaks['bool_custom_columns_are_tristate']
+
+        defs['bools_are_tristate'] = \
+                tweaks.get('bool_custom_columns_are_tristate', 'yes') == 'yes'
+        if self.prefs.get('bools_are_tristate') is None or not test_eight_code:
+            self.prefs.set('bools_are_tristate', defs['bools_are_tristate'])
 
         # Migrate saved search and user categories to db preference scheme
         def migrate_preference(key, default):