Great product. Email repaired perfectly. Alan and team had me up and running with the product again when I replaced my tired old
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Why DataNumen Exchange Recovery?
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Recover Much More than Our Competitors
Comparison of major OST to PST converter tools in the market, including DataNumen Exchange Recovery, Kernel Recovery for OST, Stellar Phoenix Mailbox Exchange Desktop, OST2PST, Recover Data for OST to PST, etc.
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Our Customers' Testimonials
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Great product. Email repaired perfectly. Alan and team had me up and running with the product again when I replaced my tired old computer.
Michael Wilhelm
Cygnet Energy Ltd.
Calgary, Canada
Nov 12, 2022
Congrats!
Your Exchange recovery software is amazing and works like a champ. Thank you.
Erwin W.
May 9th, 2020
DataNumen tool worked perfectly, did the task I needed it to do. A+ Product thank you.
Seth L
May 9th, 2020
I would like to thank you very much for making it possible to recover an email box that you already consider lost, with DataNume Exchange Recovery
I would like to thank you very much for making it possible to recover an email box that you already consider lost, with DataNume Exchange Recovery software.
Congratulations to DataNumen Team!
Nelson d'Avila
February 16th, 2020
I just wanted to say thank you for providing this program. I just used it to successfully convert a large OST file which is allowing me to recover
I just wanted to say thank you for providing this program. I just used it to successfully convert a large OST file which is allowing me to recover 150 emails that went missing.
It did a great job, and I'm super happy.
Thank you very much. I hope you have a most excellent day, and an outstanding weekend!!
Christopher Baber
Asheville, NC
May 10, 2019
By the way, we appreciate a lot your help. We made the decision of buying Datanumen Exchange Recovery tool yesterday, and one of the things we based
By the way, we appreciate a lot your help. We made the decision of buying Datanumen Exchange Recovery tool yesterday, and one of the things we based our decision was the excellent technical service that you provided while we were testing.
Daniel Navarro
April 29, 2019
Hi Team
This tool was so helpful! I've tried other similar software but this one does the trick for recovering ALL my e-mails from OST file.
Genrev
May 20, 2019
I just wanted to say you guys are the best...
You are very appreciated! Now i can get my calendar info from an incorrecty setup OST (should have
I just wanted to say you guys are the best...
You are very appreciated! Now i can get my calendar info from an incorrecty setup OST (should have had calendar info split into a pst instead of included in ost)
Thanks again and have a great day!
Gene Rovinsky
April 5, 2019
You are save my day. Anything I needed - just to convert 2 OST files. Only your program do this. Thanks a lot!
Ilya Sevryukov
Moscow, Russia
April 29, 2019
This is a great piece of software. It recovered a broken OST file first time and it then opened first time in Outlook 2019. I had tried 3 other
This is a great piece of software. It recovered a broken OST file first time and it then opened first time in Outlook 2019. I had tried 3 other pieces of repair software without success and was about to accept the old mail had been lost. Thanks heaps DataNumen! 😊
Peter Keating
ex CIO, now retired
Melbourne, Australia
July 15, 2019
Your product did all that it was supposed to do. Recovering my email data file saved me.
I will be recommending your product to anyone who needs
Your product did all that it was supposed to do. Recovering my email data file saved me.
I will be recommending your product to anyone who needs it, and for sure if i need it, i will re-install it.
Excellent product.
Alasmarh
December 26, 2019
After the replacement of my personal PC, I needed to recover for personal use the old UST file converting it to PST. Among a lot of softwares, I have
After the replacement of my personal PC, I needed to recover for personal use the old UST file converting it to PST. Among a lot of softwares, I have found DEXR.EXE that fitted exactly my purpose. Whilst the UI looks very simple, DEXR was able to recover all my emails, contacts and contact groups with no errors. I well keep in mind DATANUMEN for the future as a reference Brand for data recovery.
Roberto Baldassar
Italy
March 7, 2020
After over 10 hours of active time wasted to educate MS on what the problem is when I upgraded my Outlook 2010 to 2013 and the autogeneration of
After over 10 hours of active time wasted to educate MS on what the problem is when I upgraded my Outlook 2010 to 2013 and the autogeneration of mutiple .ost files I finally gave up. when they told me they cannot open the original .ost file. I then got the bright idea to do a quick search on .ost to .pst conversion and boom - 3.8GB of data that was very valuable to me was back in my hands - all this after MS top tier support for Outlook said they couldn't do anything. I am far from a computer geek but when you know more than the tech support rep you should figure out quickly that you are in trouble. It works...
RJ Collins Founder V360
San Diego, CA, USA
May 15th, 2015
Extremely Simple Interface
Recovery
Batch Recovery
Options
Solution for Following Common Errors and Problems in Outlook OST File
- Exchange is Currently in Recovery Mode
- Synchronization Errors
- Errors Could have been Detected in the File
- The File Is not an Offline Folder File
- Oversized OST File Problem
- Delete Exchange Objects by Mistake
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Main Features
- Support Exchange 5.0 to 2019 and Exchange ActiveSync.
- Support MS Outlook 97 and higher versions, including Outlook for Office 365 and Microsoft 365.
- Support offline OST files for IMAP accounts(e.g. Outlook.com, GMail.com, Hotmail.com, etc.), Microsoft 365 accounts, and Exchange accounts.
- Convert and recover all kinds of objects, properties, and formats.
- The recovered items are saved and converted to PST file format that can easily be accessed by Microsoft Outlook and other compatible email clients.
- Recover all kinds of deleted objects.
- Powerful OST to PST converter tool.
- Convert and recover oversized 2GB OST files.
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Using DataNumen Exchange Recovery to Convert OST to PST Files
See Video Tutorial
(Full Version)
See Video Tutorial
(Demo Version)
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 our OST to PST converter software to convert OST files to PST files so that the mailbox data inside the files can be accessed in MS 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 our conversion tool to recover data from the OST files and convert them into PST file format.
Start DataNumen Exchange Recovery.
Note: Before converting the Outlook 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:
You can input the OST file name directly or click the 
button to browse and select the file. You may also click the 
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 
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:
You can input the converted file name directly or click the button to browse and select the converted file.
You can select the format of the converted PST file in the combo box 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 
button, and our OST converter tool will start the OST to PST conversion process. 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:
Now you can open the converted PST file with Microsoft Outlook and see the converted objects. Please note our OST to PST converter software 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.
More Information
Abount DataNumen Exchange Recovery
| Version | 8.8 (What's New) |
| Release Date: | October 6th, 2022 |
| Supported Languages: | English, Spanish, French, German, Italian, Portuguese, Russian, Japanese, Korean, Simplified Chinese, and Turkish. |
Requirements
| Operating System | Windows 95, 98, ME, NT, 2000, XP, 2003, 2008, Vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11, Windows 365, and Windows Server 2003/2008/2012/2016/2019/2022 |
| Processor | Intel or equivalent(x86, x64) |
| Memory | 64 MB minimum (2 GB recommended) |
| Hard Disk | 26MB free space |
What is the difference between PST and OST files?
PST (Outlook Data File) stores the mailbox contents on your local computer, for POP accounts.
OST (Offline Outlook Data File) stores a synchronized copy of the mailbox contents on your local computer, for most other account types, such as IMAP accounts(e.g. Outlook.com, GMail.com, Hotmail.com, etc.), Microsoft 365 accounts, and Exchange accounts.
How to open or import OST files in Outlook?
MS Outlook cannot open or import OST files directly. To access the mailbox data inside an offline OST file, you need to use our OST to PST converter to perform the conversion of OST files to PST files, and then open or import the PST files in Outlook.
Why do I need to convert OST file to PST file format?
There are many cases you need to perform the conversion, including:
- MS Exchange server crashes due to various reasons.
- The Exchange mailbox becomes inactive and you need to access the orphaned OST file.
- You cannot connect to the Exchange server, such as system maintenance, downtime, dismission, etc.
- Recover deleted emails from the Outlook OST file.
- Open or access the OST file data from another Outlook profile.
- Data migration from one computer to another.
- You are using an old version of Outlook and the OST file size reaches 2GB limit.
Use OST to PST converter, you can access the OST mailbox data directly in Outlook.
Is there a free way to convert OST file to PST format?
Yes, if you can still access the mailbox data in the OST file, then you can use the manual method to export OST file to PST file, as follows:
-
- Start Outlook.
- Click File > Open & Export.
- Click the Import/Export option.
- In the Import and Export Wizard dialog box, choose Export to a file and click Next.
- Select Outlook Data File (.pst) as the file type and click Next.
- Select the folder to export from, and make sure Include subfolders is checked. Then click Next.
- Set the path of the output PST file.
- Click Finish.
- If the Outlook PST file does not exist, Outlook will create a new one. It will pop up a dialog box asking you to input the optional password for the new PST file. Just leave it empty and click the OK button.
Then Outlook will export the OST file to the PST file, which can be opened or imported from Outlook later. However, if you are unable to access the orphaned OST file, then you need to use our conversion tool to do the task.
Does your tool need to connect to the Exchange server to convert OST to PST file?
No. It does not need to connect to the Exchange server to perform the OST to PST conversion.
What are the advantages of your tool over other OST to PST converters?
Our tool has the best recovery rate and the most comprehensive features among all the OST to PST converters in the industry. You can see the comparison between it and other competitors.
Can your software convert OST emails to .msg files?
Each MSG file stored only one email. It is called Outlook Message Format. It has two variants, i.e., non-Unicode format and Unicode format. Both will use .msg as the file extension.
If you want to export emails in an offline OST file as .msg files, please do as follows:
- Convert the OST file to a PST file via our file converter.
- Start Outlook.
- Open the PST file in Outlook.
- Double-click to open the email you want to convert.
- Click File -> Save to save the email as an Outlook Message Format or Outlook Message Format – Unicode.
- Repeat steps 1 to 5 for all OST emails you want to export as .msg files.
Can your software CONVERT OST emails to .eml/.XML files?
Each EML file stores only one email. The email contents are saved as Internet Message Format.
XML(Extensible Markup Language) file can also be used to store an email.
If you want to export all emails in an offline OST file as .eml/.xml files, you need to do as follows:
- Export the wanted emails to .msg format. Both non-Unicode and Unicode formats are OK.
- Based on the bitness of your Outlook, download the corresponding version of MFCMAPI. For the 32bit version of Outlook, you need to download the one without the x64 tag. And for the 64bit version, you need to download the one with the x64 tag.
- Start MFCMAPI.
- Click Advanced -> Import/Export -> Convert MSG to EML or Convert MSG to XML to convert to .eml/.xml format.
- Keep all the default values, click the OK button.
- Select the .msg file you saved in step 1.
- Set the .eml/.xml file name and location, then click Save.
- Now you have successfully saved one email in .eml/.xml format.
- Repeat step 1 to 8 for all emails you want to export as .eml/.xml files.
Can your tool convert OST mailbox to MBOX format?
MBOX format just concatenates all messages in plain text format. You can do as follows to convert OST mailbox to MBOX format:
- Use our file converter to convert the Exchange OST file to PST file format.
- Use an email client Thunderbird to import the PST file and convert it to MBOX format.
Can your tool convert OST contacts to vCard files?
vCard file is also called Virtual Contact File(VCF) file. It is the standard for electronic business cards.
To convert OST contacts to vCard files, please do as follows:
- Convert the OST file to a PST file via our tool.
- Start Outlook.
- Open the PST file in Outlook.
- Double-click to open the contact you want to convert.
- Click File -> Save to save the contact as vCard files (*.vcf) format.
- Repeat steps 1 to 5 for all OST contacts you want to export as .vcf files.
How long will it take to complete the conversion process?
This depends on many factors, including:
- Outlook OST file size.
- The number of items in the OST file.
- The complexity of the OST file.
- The performance of your computer system.
Normally for a 10GB OST file, it will take about 2 to 3 hours to convert it to a PST file on a 64bit modern computer.
Can your tool recover corrupt OST files?
Yes, our tool can recover data from corrupt or damaged OST files and output them into a PST file.
Are there any data losses during the conversion process?
If your OST file is not corrupt, then there will be no data loss. All the items in the original OST file will be converted and saved into the new PST file. If your OST file is corrupt, then all unaffected data can be converted. For the affected data, they will also be recovered in the maximum possibility.
What is the difference between the free demo version and the full version?
The free demo version and the full version use the same recovery engine, except the former will replace the message body with a brief demo text.
Which versions of Windows are supported?
Currently, our OST converter tool supports all Windows OS versions, including Windows 95/98/ME/NT/2000/XP/Vista/7/8/8.1/10 and Windows Server 2003/2008/2012/2016/2019. And it supports both 32bit and 64bit systems.
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