Why DataNumen Exchange Recovery?

#1 Recovery Rate

#1 Recovery

10+ Million Users

10+ Million

20+ Years of Experience

20+ Years of

100% Satisfaction Guarantee

100% Satisfaction

Recover Much More than Our Competitors

Recovery rate is the most important criterion of an OST recovery and OST to PST conversion product. Based on our comprehensive tests, DataNumen Exchange Recovery has the best recovery rate, much more better than any other competitors in the market!

Average Recovery Rate

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Learn more about how DataNumen Exchange Recovery smokes the competition

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Extremely Simple Interface

Solution for Following Common Errors and Problems in Exchange OST File



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Main Features in DataNumen Exchange Recovery v7.8

  • Support Exchange 5.0 to 2019.
  • Support Outlook 97 to 2019 and Outlook for Office 365.
  • Support OST files created by Exchange ActiveSync.
  • Support for Windows 95/98/ME/NT/2000/XP/Visa/7/8/8.1/10 and Windows Server 2003/2008/2012/2016/2019. Both 32bit and 64bit operating systems are supported.
  • Support to recover mail messages, folders, posts, calendars, appointments, meeting requests, contacts, distribution lists, tasks, task requests, journals and notes in OST files. All properties, such as subject, to, from, cc, bcc, date, etc., are recovered.
  • Support to recover mail messages in plain text, RTF and HTML format.
  • Support to recover attachments, including the documents and images attached to messages and embedded in HTML bodies.
  • Support to recover embedded objects, such as another message, Excel Worksheets, Word documents, etc.
  • The recovered items are saved and converted to personal folders (PST) files that can easily be accessed by Microsoft Outlook and other compatible mail clients.
  • Support to recover deleted items in Exchange mailbox, including mail messages, folders, posts, calendars, appointments, meeting requests, contacts, distribution lists, tasks, task requests, journals and notes.
  • Support to convert OST to PST files fast and efficiently.
  • Support to recover oversized 2GB OST files.
  • Support to recover OST files as large as 16777216 TB (i.e. 17179869184 GB).
  • Support to split the output PST file into several small files.
  • Support to recover password protected OST files, both compressible encryption and high encryption(or best encryption) are supported. The OST file can be recovered even if you don't have the password.
  • Support to generate fixed PST file in Outlook 97-2002 format, Outlook 2003-2019 format, and Outlook for Office 365 format.
  • Support to recover OST file data from undamaged or damaged VMWare VMDK(Virtual Machine Disk) files(*.vmdk), Virtual PC VHD(Virtual Hard Disk) files(*.vhd), Acronis True Image files(*.tib), Norton Ghost files(*.gho, *.v2i), Windows NTBackup files(*.bkf), ISO image files(*.iso), Disk image files(*.img), CD/DVD image files(*.bin), Alcohol 120% Mirror Disk File(MDF) files(*.mdf) and Nero image files(*.nrg).
  • Support to repair and convert OST files on corrupted media, such as floppy disks, Zip disks, CDROMs, etc.
  • Support to repair and convert a batch of OST files.
  • Support to find and select the OST files to be repaired on the client computer.
  • Support to save the recovered PST file at any location, including the network attached drives recognized by the local computer.
  • Can be used as a computer forensic tool and electronic discovery (or e-discovery, eDiscovery) tool.
  • Support integration with Windows Explorer, so you can repair an OST file with the context menu of Windows Explorer easily.
  • Support drag & drop operation.
  • Support command line (DOS prompt) parameters.

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Using DataNumen Exchange Recovery to Convert OST to PST Files

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When disaster occurs on Microsoft Exchange server, such as server crashes, server database corruption, etc., the Exchange offline folder (.ost) files on the client computer still contain the mail messages and all other items of your Exchange mail account. You can use DataNumen Exchange Recovery to convert the OST files to PST files so that the data inside the files can be accessed in Microsoft Outlook.

Moreover, when you encounter various errors and problems with OST files, such as data corruption, synchronization errors, deleting emails by mistake, oversized 2GB OST file problem, etc., you can always use DataNumen Exchange Recovery to recover data from the OST files and convert them into PST format.

Start DataNumen Exchange Recovery.

DataNumen Exchange Recovery

Note: Before converting the OST file with DataNumen Exchange Recovery, please close any other applications that may access or modify the OST file. Also please close Microsoft Outlook.

Select the OST file to be converted:

Select Source File

You can input the OST file name directly or click the Browse button to browse and select the file. You may also click the Find button to find the OST file to be converted on the local computer.

If you know the Outlook version of the source OST file to be repaired, then you can specify it in the combo box Select Format beside the source file edit box, possible formats are Outlook 97-2002, Outlook 2003-2010, and Outlook 2013-2019/Office 365. If you leave the format as "Auto Determined", then DataNumen Exchange Recovery will scan the source OST file to determine its format automatically. However, this will take additional time.

DataNumen Exchange Recovery will save the converted data as a new file in Outlook PST format so that you can use Microsoft Outlook to open and see the converted objects. And by default, the new file name is xxxx_recovered.pst, where xxxx is the name of the source OST file. For example, for source OST file Source.ost, the default converted file will be Source_recovered.pst. If you want to use another name, then please select or set it accordingly:

Select Destination File

You can input the converted file name directly or click the Browse button to browse and select the converted file.

You can select the format of the converted PST file in the combo box Select Format beside the converted file edit box , possible formats are Outlook 97-2002 and Outlook 2003-2019/Office 365. If you leave the format as "Auto Determined", then DataNumen Exchange Recovery will generate the converted PST file compatible with the Outlook installed on the local computer.

Click the Start Recovery button, and DataNumen Exchange Recovery will start converting from the source OST file to PST file. Progress bar

Progress Bar

will indicate the conversion progress.

After the conversion process, if any data can be converted successfully, you will see a message box like this:

Success Message Box

Now you can open the converted PST file with Microsoft Outlook and see the converted objects. Please note DataNumen Exchange Recovery will try to put the converted objects in their original folders. However, for the lost & found objects, they will be recovered and put in special folders like Recovered_Group1, Recovered_Group2, etc.