diff --git a/forms/format_dlgs.py b/forms/format_dlgs.py
--- a/forms/format_dlgs.py
+++ b/forms/format_dlgs.py
@@ -1,4 +1,5 @@
 from PyQt5 import QtWidgets
+from PyQt5.QtWidgets import QApplication
 
 from floppyemu import format_images
 from ui import format_dialog, format_one_dialog
@@ -21,15 +22,25 @@ class FormatManyDialog(QtWidgets.QDialog
     def accept(self):
         try:
             if self.rb_size_720.isChecked():
-                format_images(self.__device, ((self.sb_from.value(), self.sb_to.value() + 1),), self.__temp_path, 720)
+                size = 720
             elif self.rb_size_1440.isChecked():
-                format_images(self.__device, ((self.sb_from.value(), self.sb_to.value() + 1),), self.__temp_path, 1440)
+                size = 1440
             else:
                 QtWidgets.QMessageBox.critical(
                     self, 'Error',
                     'Please choose image size before proceeding'
                 )
                 return
+
+            self.rb_size_720.setDisabled(True)
+            self.rb_size_1440.setDisabled(True)
+            self.sb_from.setDisabled(True)
+            self.sb_to.setDisabled(True)
+            self.buttonBox.setDisabled(True)
+            format_images(
+                self.__device, ((self.sb_from.value(), self.sb_to.value() + 1),), self.__temp_path, size,
+                self.__update_progress
+            )
         except PermissionError:
             QtWidgets.QMessageBox.critical(
                 self, 'Permission error',
@@ -40,6 +51,11 @@ class FormatManyDialog(QtWidgets.QDialog
 
         super().accept()
 
+    def __update_progress(self, indices, index):
+        self.progressBar.setMaximum(indices[1] - indices[0])
+        self.progressBar.setValue(index - indices[0])
+        QApplication.instance().processEvents()
+
 
 class FormatOneDialog(QtWidgets.QDialog, format_one_dialog.Ui_Dialog):
     def __init__(self, index, device, temp_path, parent=None):