★★★★ Uninstall all office. You can use MicrosoftFixit, a special uninstallation tool for office, to clean up the original office, or you can use Windows Install Clean, a self-made uninstallation software made by Microsoft.

Up forcibly uninstalled the originally installed office, deleted all folders and files with office on drive C, and then cleaned up the garbage and book list.

★★★★ Delete the backup files left by the update (you can also use security guards or optimization software to slim down and delete the system).

Then reinstall it.