diff --git a/src/calibre/gui2/dialogs/check_library.py b/src/calibre/gui2/dialogs/check_library.py
index 3afb1079de..8517b31209 100644
--- a/src/calibre/gui2/dialogs/check_library.py
+++ b/src/calibre/gui2/dialogs/check_library.py
@@ -8,7 +8,7 @@ from threading import Thread
 
 from PyQt5.Qt import (
     QDialog, QVBoxLayout, QHBoxLayout, QTreeWidget, QLabel, QPushButton,
-    QDialogButtonBox, QApplication, QTreeWidgetItem, QLineEdit, Qt, QSize,
+    QApplication, QTreeWidgetItem, QLineEdit, Qt, QSize,
     QTimer, QIcon, QTextEdit, QSplitter, QWidget, QGridLayout, pyqtSignal)
 
 from calibre.gui2.dialogs.confirm_delete import confirm