Top 5 Microsoft Outlook OST Recovery Tools

Outlook creates Offline Storage Table (OST) to store a cached copy of your Exchange mailbox on the local storage. Sometimes, this file becomes orphaned or inaccessible due to various reasons. In such a case, it is difficult to recover your mailbox data unless you have a backup of the file. If you don’t have a backup, you need to use a powerful OST recovery tool to recover the OST data. There are many OST recovery tools available in the market but it is difficult to decide which one is perfect for your needs. In this post, we’ll be mentioning the top 5 OST recovery tools, along with their pros and cons.

Top 5 OST Recovery Tools

Here are the top 5 OST recovery tools that you can use to recover OST data:

1. Stellar Converter for OST

Stellar is a well-known brand in the data recovery domain. The brand offers Stellar Converter for OST – a powerful OST recovery tool that can convert OST file of any size to PST format. It also allows to save the OST data in various other file formats, such as EML, PDF, HTML, RTF, and MSG. The software offers a user-friendly interface that helps convert OST file in a few simple steps.


  • Converts inaccessible or orphaned OST files of all sizes into PST
  • Recovers all OST mailbox items, including emails, contacts, journals, attachments, notes, etc.
  • Allows selective recovery based on filters, such as Subject, Date, To, From, etc.
  • Offers multiple options for saving the recovered mailbox data – PST, EML, PDF, RTF, HTML, and MSG.
  • Allows you to directly export OST to Office 365 account, Outlook profile, and Exchange account (Technician edition)
  • Supports batch conversion to recover multiple OST files in a single session (Technician edition)
  • Splits and compacts large-sized OST files (Technician edition)
  • Previews recovered OST file in a neat three-pane window
  • Supports MS Office 365, 2019, 2016, 2013, 2010, and 2007


  • The software’s demo version allows to save only 10 items per folder

2. SysTools OST to PST Converter Tool

The OST to PST Converter application from SysTools is another Microsoft Outlook recovery tool to convert OST file data to PST format. It can convert orphaned or inaccessible OST file of any size to PST and other formats.  


  • Converts OST files, including encrypted OST files, into PST
  • Recovers all items, such as emails, attachments, notes, calendars, etc., from an inaccessible Offline Storage Table (OST)
  • Splits large-sized OST into small PST files
  • Saves recovered OST data in PST, HTML, MSG, and EML file formats


  • The software requires installation of .NET framework to function properly
  • There is no option to compact the saved PST files

3. Aryson OST to PST Converter

Aryson OST to PST Converter is another reliable OST recovery tool that you can consider to recover .OST file. One important feature that makes this tool special is the option to save OST in MBOX format.


  • Converts encrypted and large-sized OST files into PST without any issues
  • Restores complete OST mailbox data, including emails, attachments, journals, etc.
  • Saves OST into PST, EML, and MBOX file formats
  • Splits the converted PST file based on size and date
  • Creates a log of OST to PST conversion process


  • The software’s demo version allows to save only 20 emails per OST file and in only EML format
  • Doesn’t support recovery of deleted items
  • Incompatible with Outlook 2019
  • Doesn’t export restored OST to Office 365

4. Kernel OST to PST Converter

Kernel is another well-known name in the IT domain. Its OST to PST converter is highly recommended by tech experts for recovering lost or deleted OST items.


  • Converts all OST items, including emails, calendars, contacts, etc., to PST
  • Saves the restored OST file in PST, RTF, MSG, PDF, and TXT file formats
  • Exports OST to Office 365 account
  • Splits large PST file into smaller files (Corporate license)
  • The demo version allows to save 25 items per folder for free


  • Deep scanning the deleted items in OST takes a long time
  • No option to compact the final PST file
  • Works slowly when processing large OST files

5. Atom TechSoft OST to PST Converter Software

This OST recovery tool from Atom TechSoft offers the highest number of file format options for saving the converted file. It offers a risk-free and speedy recovery of inaccessible OST files.  


  • Converts OST to PST efficiently and quickly
  • Saves recovered OST file in HTML, MSG, MBOX, RTF, PDF, DOC, TXT, and other formats
  • Splits large PST file into small files (from 1 GB to 5 GB)
  • Offers message filtering option for selective recovery


  • No option to export restored OST file to Office 365 or Exchange Server
  • No feature to compact the recovered OST data
  • UI is generic/outdated


It is not possible to recover mailbox data from an orphaned OST file by using Outlook. You need to use an OST recovery tool to extract data from an orphaned OST file. In this post, we’ve mentioned top 5 OST recovery tools that can easily recover data from orphaned OST files. You can compare these OST to PST converter tools and choose the one that suits your requirements.

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