How To Solve Error OST Is Not an Outlook Data File?

“I had a problem with my system hard disk, so I had taken backup of my data to another removable hard drive. Once I replaced the system hard drive, I copied back my data to it. On opening emails, I noted that my .PST file is changed to .OST and thus I was unable to open it. When I try to open Outlook, I get an error like “The file you have chosen is not an Outlook data file. You must select a new file of this type”. How do I open this? Do I need to convert the .OST to .PST?”

The Microsoft Outlook application can access only .PST file and it cannot access the .OST file. The OST file is an exact replica of Microsoft Exchange Server mailbox stored in user’s local computer. An OST file is an offline folder which allows the users to work offline and then synchronizes the changes made in OST file with Exchange Server; same way the modifications done in Exchange Server will be altered on OST file.

If your OST is not properly synchronized with MS Exchange Server or OST file is corrupted, then you may encounter this kind of errors. When you come to know that your OST file is corrupted or inaccessible, then use in-built repair tool (Scanost.exe) to fix it. The Scanost.exe can fix corrupted OST file to certain extent only, if your OST file is severely corrupted or damaged then Scanost.exe tool will not be able to fix this issue. In that particular case, you need to convert OST file to PST file with the help of effective third party tool. The OST to PST conversion utility can repair corrupt OST file during conversion process and then converts OST file to an Outlook accessible PST file.

OST to PST conversion utility:

Yodot OST to PST Converter is the perfect conversion tool which helps you to convert OST file to accessible PST file and resolves the error OST file is not an Outlook data file. Many email application users employ this OST file conversion tool to convert OST to PST file in order to resolve OST file issues for regaining access to their Outlook account. It is a read-only program that doesn’t modify the contents of original OST file. Instead it extracts the data from OST file and re-generates a healthy PST which is accessed by Microsoft Outlook. The conversion is very simple and you can restore all your Emails, Contacts, mail attachments, tasks, Calendar items, notes, journals and other Outlook items after converting OST to PST file on Windows system.

Procedure for converting OST to PST file using conversion tool:

  • Download and install Yodot OST to PST Converter software on your Windows computer
  • Launch the software either by using shortcut icon on desktop or from Start menu
  • In main screen, you get two options i.e. “Open OST File “ and “Find OST File”
  • Select “Open OST File” if you know the exact location of OST file on your system
  • Else, select “Find OST File” to automatically find the location of OST file on your system
  • In next Tab, you can select destination path to store the converted OST file
  •  Click on “Convert” button to start conversion process and you can see progress bar in next tab
  • After conversion, you will receive confirmation message like ‘OST file conversion is successfully completed’
  • Open your Microsoft Outlook application and import the newly created PST file to regain your Outlook items back


  • If you encounter any problem with PST or OST file, then first try to fix it using Scanpst.exe repair tool
  • Regularly update your antivirus application in order to protect Outlook data files from virus and harmful threat infection
  • Keep an additional copy of OST file, so that it can be used when PST file gets damaged or corrupted