The File menu displays a list recently opened documents. This may include files from a previous session.

You can restore a backed up document.

By default, backups of open files are automatically saved. Under the Options dialog from the Tools menu, you can change the frequency of AutoSave or disable this feature. See the Options>General page for details.

To restore backups:

From the File menu, select Recent Documents, then Restore Backup. All backed up files are opened.