OST2PST Viewer lets you view .OST offline mailbox data files. It has a preview option available for both messages and attachments and displays all items such as task, journals, calendars etc.

With OST2PST Viewer you can opens orphan .OST data files from Outlook. It lets you read both ANSI and UNICODE .OST data files, and provides a view of all types of .OST files: Encrypted, Highly Encrypted, & Compressed, Download, and Safe download.

OST2PST Viewer has a simple interface and is viewable on any kind of computer. In order to open .OST file without Outlook you simply click on Add file and then browse .OST file. The app will then load all the data of the selected .OST file. It also comes with a dual preview option that enables you to easily preview any messages or attachments in the same screen. In the dual view there are two sections, one displays all items of selected folder the other shows you preview. It contains two tabs, one to preview the selected message and the other shows its attachment.

The great thing about OST2PST Viewer is that it is not dependent on Outlook being installed on your system. It provides the same view of Outlook offline Mailbox data files as you would get in Outlook. You will see same folder and sub folder structure, and even the message formatting remains the same. All read and unread message status is also maintained.