MailsDaddy Free OST file Viewer is a free tool to view damaged and orphaned OST files. You can open the OST file in Microsoft Outlook and without an Exchange Server connection. You can preview OST file mail properties like To, From, Subject, Cc and Bcc when you load OST file once with ease. It can easily view contacts and calendars from OST file. It is beneficial with all Outlook versions like Outlook 2019, 2016, 2013, 2010, 2007 and 2003.