OST Converter

For Win





For Mac





SysTools OST Converter Tool
Best Software to Convert Microsoft Outlook OST Files into Multiple Formats

(Average Rating 4.5 Based on 1178 Reviews)
  • Convert OST emails, contacts, calendars, attachments and other information
  • Convert OST Files into Multiple Email Format PST, MBOX, MSG, EML, EMLX, NSF
  • Export into Document Format PDF, vCard, CSV, ICS, TXT, HTML, MHT, DOCX, DOC, RTF
  • Ability to export large / corrupted / inaccessible / orphaned Outlook OST files
  • Preserves and convert Unicode OST content to selected format and save
  • Provided support to run the tool as Standard/Guest user without asking Admin Privilege
  • OST Converter exports Exchange, IMAP, Office 365, & Hotmail OST Files
  • Remove and Decrypt S/MIME & OpenPGP encryption from OST file emails
  • OST Converter Tool supports all the available versions of Windows & Mac OS

Free Live Demo: – SysTools Outlook OST Converter Wizard Fully Secured Download Version

OST Converter Awards and Reviews

Expert Rating of OST File Converter Application

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OST Converter Software - Highlighted Features

Most Powerful OST Converter Tool to Export Corrupted, Damaged, Password Protected OST Files

ost converter

Supports Batch Conversion Feature By Using Search Option

OST Converter is an advanced utility that allows to export multiple OST files into selected file format in a single go. Moreover, it provides different options to add the OST files that include:

  • Select File: In case if you know the exact location of your Outlook OST file, then choose this option, navigate and add the Outlook OST file you want to convert.
  • Search File: If the location of the OST file is unknown then, this option will allow you to search and locate the OST file automatically in your system drives. You can search your OST files in two ways:
  1. Search Selected Drive: This option will allow you the locate the Outlook OST file within a particular system drive. One just needs to choose the suspected system drive (like C, D, E) and if the file is there, OST Converter Tool will locate it.
  2. Search All Drive: In case if you have no idea where your OST file could be then, this software facility will scan all the system drives and locate detected OST files quickly.

Download Wizard

7+ Modes to Preview Outlook OST File Content

Right after loading the OST file in this Tool it starts scanning the file and loads it in the software panel. From here one can preview OST items in the following modes:

Note: - You can select multiple files by pressing Shift + Arrow Key in the check boxes.

  • Normal Mail View:Display OST emails normally as Outlook and includes information like From, To, Cc, Bcc, Subject, Attachments, etc.
  • Hex: Encode every bit of information and preview Outlook OST emails in hexadecimal format. Best preview mode to analyze data from forensic point of view.
  • Properties: View additional email details like Internet header, Message Flags, Sender Description, Body, etc.
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  • Message Header: Select an email and check different emailing properties like MIME-Version, Date, Message-ID, Content-Type, Priority, etc.
  • MIME: Select and check OST emails in Internet standard including details like MIME-Version, Date, Priority, To, Cc, Content-Type, Content-Transfer-Encoding, etc.
  • HTML: Check Outlook OST email data in HTML coding, which is specified with proper HTML tags.
  • RTF: Preview OST information in plain text RTF formatting and check the email details like style, body, tables, etc.
  • Attachments Check and preview all the integrated OST emails at one place. Preview any type of attachment like .jpg, .png, .docx, .csv, .txt, .pdf, etc.

ost converter wizard

OST Converter - Multiple Export Options

The OST File Converter Tool provides so many advance export options to process the OST file conversion. Some of the options are following:

  • Maintain Folder Hierarchy: Choosing this option will retain the original OST folder structure as it is throughout the OST conversion process. All the folders or subfolders within the added OST will retain the same even after exporting the OST file.
  • Don’t Export Empty Folder: In case if the added OST comprises folders with no data then, check this option to skip the conversion of empty folders.
  • Use Outlook: This option requires MS Outlook installation and proper configuration for a quick OST conversion.
  • Ignore System Folders: If you don’t want to convert your system folders, then check this option to skip the system folders during OST conversion.

OST Converter Software - Key Features

Convert Outlook 2021, 2019, 2016, 2013, 2010, 2007, 2003, 2000 OST Files Safely

convert all types of OST

Export OST to Different Formats

OST File Conversion Tool is an ultimate solution to convert Outlook file formats file format instantly. The software is capable enough to convert all the data items of an OST file like Emails, Contacts, Calendars, Tasks, Attachments, and others. After conversion, OST files can be accessed from multiple email clients and supported applications including MS Outlook, Mozilla Thunderbird, Adobe Acrobat Reader, and Web Browsers.

Scan Modes

Quick and Advanced Scanning Modes

Right after adding the OST file in the software, it provides two different options to scan the OST file. The first option is Quick Scan, which scans the added OST quickly and loads the entire content in software pane. Another option is the Advanced Scan. In case if the added OST file is highly corrupted or damaged then, choosing this option will scan the entire OST thoroughly, recover entire OST data and load it in the software.

convert inaccessible ost

Export OST Regardless of Size / Type

The OST converter can convert all types of OST files. So no matter if the OST is orphaned, corrupted, highly damaged, inaccessible, password protected or created by IMAP, Exchange, or Office 365 accounts. The software can convert OST files simply even without resulting in any kind of data loss. Besides, it can handle the conversion of large-sized OST files into the desired format efficiently.

preview ost data with metadata

Preview OST Items With Meta Properties

Once the scanning gets completed successfully, the OST Conversion Software loads the file data and displays an instant preview of OST items. One can preview OST data in 7+ preview modes including Normal Mail View, Hex, Properties, Message Header, MIME, HTML, RTF, and Attachments as well. From here, one can preview all the OST items including emails, tasks, contacts, calendars along with their metadata. For example: To, Cc, From, Subject, Attachments, etc. Permanently deleted items will be displayed in Red color and recovered folders with data will be highlighted in bold.

convert ost file in batch

Different Options to Add Outlook OST file download free software

The OST Converter software allows to convert single as well as multiple OST files at once. It provides 2 handy options to add OST files in the software:

  • Select File: This option allows to manually add a single OST file at once
  • Search File: Allows to automatically search and add multiple Outlook OST files from a Selected or All System Drives.

support Outlook 2019 and below

Supports All Versions of MS Outlook & Windows

OST Conversion Software is a powerful software that supports OST file generated by all the available versions of MS Outlook. The supported versions include Outlook 2021, 2019, 2016, 2013, 2010, 2007, 2003, 2000. Moreover, the software is compatible Windows 11, 10, 8.1, 8, 7, and all below versions of Windows OS and Mac OS X. This means it can be installed and operated easily in all the versions of Windows and Mac OS X.

decrypt ost file emails

Decrypt S/MIME or OpenPGP Encrypted OST

In case if the added OST is encrypted with S/MIME (Secured Multi-purposeInternet Mail Extension) or OpenPGP (Pretty Good Privacy) encryption, then OST File Conversion tool will decrypt the file. Once decrypted, users can convert the OST into any of the desired export option and the resultant file can be accessed simply without using any Certificates or Private Keys.

multiple ost file conversion

Convert Multiple OST Files in Batch

The software allows to add single or multiple OST files at once. It provides different options to add Outlook OST files and once added, it will convert all the OST files into selected file format quickly. No matter how many OST files are added in the software, it will export all of them at once and create separate resultant files for each OST. Moreover, one can download the complete OST conversion report in CSV format for future reference.

OST Converter Software – Specifications
All in One Solution to Convert Outlook OST Mailbox Data Items into Multiple File Format
best software


Name: SysTools OST Converter
Version: 10.0
Size: 85 MB
Release Date: August, 2023
UI Languages: 20
MD5: 4210d66216102a3ba1efd525a0f6aec3
Free Version: Download Now


Name: SysTools OST Converter for Mac
Version: 4.0
Size: 80.7 MB
Release Date: February, 2024
UI Language: English
MD5: 833d595b0df076bb6b6b8415d8a94344
Free Version: Download Now

Trial Limitations

Free Demo version of OST Converter software will generate Preview of OST mailbox data & Support to Convert only 25 Items per Folder from Outlook OST file to converter, MBOX, vCard, EMLX, NSF format.

System Specifications


Hard Disk Space
100 MB of free hard disk space required

4 GB of RAM (4 GB is recommended)

Intel® Core™ 2 Duo CPU E4600 @ 2.40GHz 2.39GHz


Hard Disk Space
100 MB of free hard disk space required

4 GB is recommended

Mac Computer with Intel Processor
Mac Computer with Apple Silicon (Apple M1)

Supported Platforms


Windows 11 (64-bit), 10, 8, 7 (32-bit or 64-bit) & Windows Server 2022, 2019, 2016, 2012 R2, 2008

Compatible with Microsoft Outlook 2000, 2003, 2007, 2010, 2013, 2016, 2019, 2021 (32/64 bit)


MacOS X 10.8 (Mountain Lion), MacOS X 10.9(Mavericks), MacOS X 10.10 (Yosemite), MacOS X 10.11 (El Capitan), MacOS X 10.12 (Sierra), MacOS X 10.13 (High Sierra), MacOS X 10.14 (Mojave), MacOS X 10.15 (Catalina), MacOS X 11.0 (Big Sur), MacOS X 12.0 (Monterey), MacOS X 13.0 (Ventura), MacOS X 14.0 (Sonoma)

Application Pre-Requisites


  • Microsoft .NET framework 4.5 or above should be installed.


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Feature Comparison Of OST Converter Tool

Get an Overview of Outlook OST File Converter Features – Free and Full Version

Features DEMO Version FULL Version
Add and Export Single or Batch OST File
Two Scanning Mode (Quick & Advanced) for OST
Preview OST Emails with Attachment
Remove S/MIME & OpenPGP Encryption from OST File
Supports Windows 11, 10, 8, 7 (32 bit or 64 bit) & Windows Server 2019, 2016, 2012 R2, 2008
Convert Outlook OST to File to 15 Formats 25 Items/Folder All Items
Cost FREE $49

Common Questions Asked by User

Most Common Queries Related to Outlook OST File Converter

How to convert OST file?

“I’m having an OST file and I want to convert it into some other format like file formats so that I can access it from some other platform than Outlook. How can I convert OST file?”

ost file converter

Steps to convert Outlook OST files:

  • Step 1 –: Download & Run SysTools OST Converter Tool
  • Step 2 –: Search or manually add OST file in the software
  • Step 3 –: Scan OST and preview data items with attachments
  • Step 4 –: Convert multiple OST files into any selected format

“I want to convert an OST file when the original server is gone and I’m left with an orphaned OST. My original server was W2K3 SP2 w/ E2K3 SP2. So, do I’ve to rebuild the server the same as it was before along with passwords to convert an orphaned OST? Any idea?"

Yes. With SysTools OST File Converter Tool is possible to convert an orphaned OST into any of the selected file formats even without rebuilding the server or installing the supported application.

"“Initially we were using MS Outlook in our organization and now shifting our data to some other email client. But, the problem is we have large-sized Outlook OST files. How to convert bulky OST files?"

SysTools OST Converter Tool is the best answer to this question. The software allows to add and convert any sized OST file into any of the selected file format quickly. There is no OST file size limitation imposed by the software, so you can add and convert any sized OST file using this.

"I have 3 GB of Offline OST file, I have taken backup of OST file. What should be the process if I want it to re-import on Exchange Server?"

Yes. The OST File Converter software is capable enough to export attachments associated with OST file emails. It can export all type of attachments including .png, .jpg, mp3, .docx, etc.
Yes. SysTools OST Converter Tool does not require a live Exchange connection in order to convert the OST file. So, you can convert OST without an Exchange connection.
BAK file is a replica of original OST and comprises all the OST data items like emails, contacts, tasks, calendars. So, you can use SysTools OST Export Tool to perform outlook.bak file conversion into any of the selected format.
Since SysTools does not provide any crack version of the OST Converter Tool so, it is highly recommended not to download it from some other sites, which claims that they have a crack version of SysTools OST file Converter application. If you do so, SysTools will not be responsible for any issue. It is suggested to download only digitally signed software for complete technical support and surety.

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