Top 5 Free OST Viewer Software

OST is encrypted by default with MAPIEntryID GUID. Thus, OST is bound to the MAPI profile and requires authentication to access the mailbox data stored in it. But if the OST file gets damaged due to Outlook crash or other system errors, it may become inaccessible. Further, if the MAPI profile is deleted or removed from the mail server, the Outlook OST enters into an orphaned state and can’t be accessed from any Outlook profile.

However, you can view any OST file, including orphaned and inaccessible OST file, by using an OST viewer tool. The software allows you to view and extract mailbox items stored in Outlook OST data files without authentication. The tool also helps you get back access to mailbox items stored in inaccessible, damaged, or orphaned OST files.

List of Top 5 Free OST Viewer Software

Below we have discussed 5 free OST viewer tools that you can download on your Windows PC to scan and read OST file without any size limit.

1. Stellar Viewer for OST

Stellar Viewer for OST is an easy-to-use free OST viewer software that comes from Stellar®, one of the most reliable and trusted data care brands in the world. The software enables you to search, scan, and preview mailbox items stored in an OST file. It also provides search options and filters, such as the ‘subject line’, ‘From’, ‘To’, ‘CC’, ‘BCC’, to locate and view specific emails or mail items. Further, it also allows users to save or export the mailbox items to EML, RTF, MSG, PDF, or HTML formats.

With the help of Stellar Viewer for OST, you can also view, read, and convert an inaccessible or orphaned OST file without authentication.

Pros

• Opens OST file without Outlook or Exchange
• Retains folder structure and hierarchy
• Scans and previews inaccessible, orphaned or damaged OST files
• Search option to quickly find and view specific emails
• Previews all mailbox items, including emails, calendar, contacts, notes, tasks, etc.
• Saves OST mailbox items in EML, MSG, RTF, HTML, and PDF formats
• 100% free OST viewer software

Cons

• No option to export mailbox items in PST format

2. Xst Reader

Written in C#, the Xst Reader is an open-source and free OST viewer software that allows you to view and read both OST and PST Outlook data files. It requires .NET framework 4 to run. However, it can open and preview the OST file without Outlook installation. 

Xst Reader scans the OST file and displays all mail contents in a three-pane window. It previews all mailbox contents and properties. Further, you can export the emails from OST file to HTML, Plain Text, or Rich Text Format (RTF).

Pros

• Open-source OST Viewer software
• Scans and opens both OST and PST Outlook data files
• Search option with CC and Bcc names
• Displays emails with date and timestamp
• Exports single or multiple emails to HTML, Plain Text, or Rich Text Format
• Exports contacts and messages in CSV format

Cons

• Limited export options
• GUI is quite basic
• Search option with limited filters

3. Stellar Converter for OST

Stellar Converter for OST is another software from Stellar® that can be used to view OST files. It’s a powerful OST to PST converter software that scans, previews, and converts OST files to PST format. Besides PST, you can also use the software to export mail items from an inaccessible or orphaned OST file to an existing Outlook profile, live Exchange, or Office 365 account.

You can also use the software to backup OST mail items in PST format and then open or import the PST in any Outlook account to access or view mailbox items.

Pros

• Opens and scans healthy and corrupt OST file of any size
• Option to find and locate OST files
• Previews all mail items, such as emails, attachments, contacts, notes, journals, etc.
• Exports mailbox items from OST to PST or existing Outlook profile
• Option to import OST to live Exchange or Office 365
• Multiple saving options, such as EML, MSG, RTF, HTML, and PDF
• Retains folder structure and hierarchy
• Saves scanned OST file information for quick access and recovery
• Automatically recovers and displays accidentally deleted mailbox items from OST file

Cons

• A freemium software. You can view OST file but need a license key to export mail items to PST and other formats

4. SysTools OST Viewer

SysTools OST Viewer is a free OST viewer tool that lets you read and open orphaned, inaccessible, or corrupt OST file without Outlook. The software provides a free preview of OST mailbox data, such as emails, attachments, contacts, notes, calendars, etc.

Pros

• Opens and displays OST file content without Outlook or any dependency
• Scans and previews corrupt, inaccessible, or orphaned OST file via Advanced Scan Mode
• Option to search and sort emails by attributes, such as To, From, Subject, etc.
• Recovers deleted mail items from OST
• Previews emails with attachments
• Keeps folder structure intact

Cons

• No option to save scanned OST mail items
• Option to search specific emails and export to PDF is not available in the free version

5. Aryson OST Viewer

Aryson OST Viewer is another free OST viewer software that allows you to open and view OST file contents without Outlook. The software helps you preview emails and other mail items from any OST file, irrespective of file size. It can also open encrypted or password protected OST file without any issue.

Pros

• Opens and previews both healthy and corrupt OST file
• Provides an option to find OST files on the system
• Reads and displays contents of severely corrupt OST file via Advanced & Deep scan options
• Previews all OST file mail items, such as emails, contacts, attachments, tasks, notes, etc.
• Exports OST mail items to Plain Text and HTML formats

Cons

• Saves OST data in HTML and Plain Text formats only

Conclusion

In this post, we’ve discussed top 5 free OST viewer software that you can download to view and read a healthy, orphaned, or inaccessible OST file. Some of these OST viewer tools lets you save the OST data to various formats, such as PST, EML, MSG, RTF, HTML, and PDF or existing Outlook profile, live Exchange, and Office 365 account.

Based on your requirement, you can choose and download any of the listed OST viewer software to open, view, convert, or export OST files. In case you need any help in choosing the best free OST viewer software or want to know something specific about the free OST viewer tool, reach us via comments down below.

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About The Author

Ravi Singh

Ravi Singh is a Senior Writer at Stellar®. He is an expert Tech Explainer, IoT enthusiast, and a passionate nerd with over 7 years of experience in technical writing. He writes about Microsoft Exchange, Microsoft 365, Email Migration, Linux, Windows, Mac, DIY Tech, and Smart Home. Ravi spends most of his weekends working with IoT (DIY Smart Home) devices and playing Overwatch. He is also a solo traveler who loves hiking and exploring new trails.