Free OST to PST Converter Tool

Achieve Precise Result via Ensured OST Recovery App.
Recover Corrupt OST Emails/ Contacts/ Attachments etc.
Export OST Files to Outlook PST, MSG or EML File Format.

A Superior Tool to Exchange OST File to PST File Risk-Free

Start Download

Click at Download Button and Install Free OST Recovery product on any available Windows OS (Supports both 32 bit-64 bit) to check all the conversion and .OST file recovery steps soon.

Free OST PST Converter edition is being rendered to users free of cost to illustrate the actual functionality and potential of Outlook OST Recovery software. An absolute and secure solution to convert OST to PST is being provided that aims to repair OST file and recover lost data from damaged/corrupt or inaccessible Outlook OST file. Trial key of the solution tool aids to transfer & stores initial 25 items folder wise.

Praiseworthy Attributes of OST to PST Conversion Utility

Corrupt OST File Conversion

With our Exchange OST2PST converter, users are facilitated to convert both damaged and healthy OST file to Outlook PST. The software offers assist while Exchange is down or OST file is corrupt resulting in synchronization failure.

Absolute Data Migration

The OST converter software ensures complete data transfer while file conversion. Emails, contacts, calendars, notes and journals get migrated with our tool to exchange OST file to PST file and without wasting your precious time.

Deleted Email Recovery

If the email is accidently deleted from mailbox permanently, the software offers advanced scanning mode to retrieve & restore accurately. The free OST to PST conversion utility assures recovery of deleted emails from OST file hassle free.

Multiple Saving Options

The software offers 3 options to save OST file after recovery. Once the Offline folder is recovered, users can save the OST file as PST, MSG and EML. This option in OST to PST tool ascertains data accessibility in several mail applications.

Resolve Error Messages

With OST to PST free converter edition, users can fix the error messages that pop up on screen, leading to data inaccessibility. Our tool allows resolving warning messages that restricts opening the OST file.

Quick Preview Of OST Files

The software has powerful scanning algorithms embedded at the backend. It gives instant preview of OST component like emails, notes, tasks and folders saved in it to satisfy users about complete data recovery & conversion.

Supports Windows & Outlook

The software gives the opportunity to convert OST to PST of any of the Outlook editions. In addition, OST to PST freeware and licensed edition can be installed on all versions of Windows OS (both 32 and 64 Bit).

Spit Oversized PST File

While Converting OST in PST you can utilize the Split PST option to break the heavy or oversized PST into small size file, once specify the size in GB tool will divides the OST in several equal sized PST File.

Let's Elucidate Why We Choose OST To PST?

  • The reason why organizations prefer collaborative platform of Outlook and Exchange Server is their facility for business continuity through Offline Folders. In case the connection between the client and the Server breaks down, OST file acts as a rescuer, a disaster recovery option.
  • Emailing being one of the crucial part of enterprises cannot be afforded to be lost due to any reasons. OST file vulnerability to corruption owing to reasons like oversized OST file, damage to Exchange database, changes done in Exchange profile file leaving it orphaned etc result in data loss.
  • The idea to open Outlook PST to Outlook PST file give users a platform to work around the consequences of corrupt OST file that includes error messages on screen, un-ability to open OST file after synchronization, inaccessibility over complete OST file data etc. An offline folder when converted to PST enable users to access entire data in a standalone application.

Let us Elaborate the Problem of OST file Corruption

Consider a Scenario: In Microsoft Outlook edition 2002 and below it, OST file that gets created has the maximum data storage limit of 2GB only. When this default limit exceeds, it can lead to corruption of OST file. Under such situation, error messages like "Cannot open or load the OST file at all" or "Cannot synchronize the OST file with the Exchange server" can be encountered by a user.

However, Outlook does not provide any kind of pre-warning about the upcoming consequences of oversized OST file. Nevertheless, there are some service packs released by Microsoft that gives users a message that OST file is approaching default size limit and more data should not be added to it. This criteria is successful to some extent in preventing OST file corruption but once the defined size limit is crossed, problems like email sending/receiving failure, synchronization etc will be troubled and this is when need for some efficient solution to convert OST file to PST file arises.


Symptoms of Oversized OST File: As a result of oversized OST file, following error messages on screen gives the indication of corruption:


  • Errors in background synchronization: In most cases, more information is available in a synchronization log in the Deleted Items folder.
  • Task 'Microsoft Exchange Server' reported error (0x00040820): 'Errors in background synchronization. In most cases, further information is available in a synchronization log in the Deleted Items folder.

However, these error messages can be fixed with a reliable solution to repair OST file tool like our OST Recovery. Our solution is integrated with potential to fix OST file after intense corruption issues and ensures that originality of data is maintained after OST to PST conversion.

How To Locate OST File?

Before starting up the process to convert OST2PST, it is necessary to have the location of OST file so that while the software asks for file location, a user can easily select it to precede Exchange OST file to PST file conversion. For different versions of MS Outlook, locations for OST file in the system will be different.

For Outlook 2007:

  » Start Outlook » Tools » Account Settings » Click on "Exchange Server" and then click on "Change".
  » A "Change E-Mail Account" window will pop up on screen» More Settings» Microsoft Exchange windows» Advanced Tab» Offline Folder File Settings» A Dialog Box appear with location of OST file.

For Outlook 2003 or Older Versions:

  » Tools » E-Mail Accounts» View or Change existing account» Microsoft Exchange Server and click Change» More Settings>> Advanced Tab »Offline Folder File Settings.

However, to move out of trouble of locating OST file for OST to PST conversion, OST Finder software can be utilized. This tool when installed in the system enlists all the Outlook accounts within the domain and for respective account gives location of OST files. The entire information about OST file location will be provided in CSV file.

How To Configure OST File Size Limit For OST File

Microsoft Outlook 2000/2002/2003/2007/2010/2013 support ANSI and Unicode OST file, depending upon the edition of the email client installed. The file size limit of Outlook OST file can be set using following four registries:

  • For Unicode OST File:MaxLargeFileSize registry entry and WarnLargeFileSize registry entry. The increment values are set in megabytes.
  • For ANSI OST File: MaxFileSize registry entry and WarnFileSize registry entry. The increment values are set in bytes.
  • MaxFileSize registry entry defines the maximum size up-to which an OST file can grow. Once the OST file reaches the defined size, Outlook does not permit the file to grow.
  • WarnFileSize registry entry defines the maximum amount of data that can be stored in Outlook OST file. Once the OST reaches the defined size, Outlook does not allow user to mount more data in it.

Note: The registry entries WarnLargeFileSize and WarnFileSize do not activate any option in Outlook that will give an alarm before file reaches the maximum size.


How to Locate Registry Entries In Registry Editor:

  » Outlook 2010 » HKEY_CURRENT_USER\ Software\ Microsoft\ Office\ 14.0\ Outlook\ OST/PST
  » Outlook 2007 » HKEY_CURRENT_USER\ Software\ Microsoft\ Office\ 12.0\ Outlook\ OST/PST
  » Outlook 2003 » HKEY_CURRENT_USER\ Software\ Microsoft\ Office\ 11.0\ Outlook\ OST/PST

To configure the OST file size limit, follow the steps mentioned below:

  • Open the Registry Editor by going to Start>>Run>> "Regedit"
  • Expand the option HKEY_CURRENT_USER in the left panel
  • Expand the Software Option>>Microsoft>>Office
  • For Outlook 2007, expand 12.0 or for Outlook 2010 expand 14.0 etc.
  • Click on OST and from the right panel click on MaxFileSize
  • Define a value for OST file size in box and click OK.

Follow the same steps for other registry entries.

System Requirements & Versions Supported

For flawless working of free OST to PST tool, it is necessary that all basic system requirements are satisfied. To the software, there are minimum system requisites. Our solution works well with all versions of Microsoft Outlook and Windows Operating System. However, it is suggested to first properly check out if the system has required space and hardware to support smooth conversion of OST file to PST so that lack of any system element do not spoil the recovery and conversion process. Here is a list of system requirements needed to work with our OST to PST free converter edition.

System Must Be Configured With

  • MS Outlook
  • Outlook Component
  • Outlook Profile Configured
  • Access to File System

Supported Versions of MS Outlook:

MS Outlook 97, 2000, 2002, 2003, 2007, 2010, 2013


Supported Versions of MS Exchange

MS Exchange 5.0, 2000, 5.5, 2003 and 2007, 2010 or 2013


Supported Windows Operating System

Windows 2000, 2002, 2003/08, 2007, Vista, XP, Win7, Win8


Basic System Requirements-

  • Pentium Class Processor
  • 64MB RAM (128 recommended)
  • Minimum 25 MB Space

Therefore, for working with our tool to repair OST file, no external set up is needed to be installed on the system. The software ascertains that complete OST to PST conversion process is executed smoothly and with support to Windows edition; it is being taken care that Operating System does not hinder the recovery process.

Do I need to have Exchange Server set up for converting OST to PST?
No, to convert OST file into PST, you need only MS Outlook installation on machine. There is no requirement for Exchange Server setup.
What if the maximum size of OST file that can be recovered?
There is no file size limitation of OST file for recovery. OST file for any Outlook edition and any size can be added to the tool for recovering it to PST.
I cannot open my OST file. Will the software repair it?
The software will recover mailbox contents from OST file to PST, MSG, or EML. As per convenience, the output files can be opened in supported mail client.
Do I need to run the software on Windows 8 edition?
Yes, the software works with all versions of Windows Operating System which includes Win 8.