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It converts an entire OST file, or items within an OST file, into a PST without changing the original content format or structuring. Read More Read More


Stellar OST to PST converter has worked wonders for Outlook 2003 to 2016 conversions of OST Files. This application I use and resort to. Read More


Key features


Get importable PST of your inaccessible OST

Use the software to easily import your data locked inside a corrupt, orphaned or inaccessible OST file in Outlook and restore mailbox access. How? Stellar Converter for OST imports OST file in Outlook. The software extracts mailbox data from the inaccessible OST file in a PST file which can be readily imported in Outlook client installed on any machine. The built-in Import Export Wizard in Outlook can help you extract OST data in PST format, but this utility takes technical proficiency and time. It also requires the same Exchange account to import OST data in PST, and also you cannot convert corrupt OST files with it. Stellar Converter for OST offers a faster and convenient way to import OST file in Outlook via a rich GUI.


Import complete OST mailbox data in Outlook

Use the software to import your complete OST file data including emails, attachments, contacts, calendars, tasks, etc. into PST format. Alternatively, you can also choose specific emails or other mailbox items from the OST file for conversion to PST. Simply open the inaccessible OST file through the software interface, then search and save individual emails. It can also extract the OST data in MSG, EML, RTF, HTML, and PDF formats. You also get enhanced preview of emails, calendars, and deleted items before actual conversion. The free trial of the software extracts up to 20 emails per folder stored in the OST to PST which can be imported in Outlook.


Import encrypted OST files in Outlook

You may have encrypted your OST file to secure the data, but what happens if you forgot the password or decryption key? Use Stellar Converter for OST which extracts the mailbox data from encrypted OST file and saves it in PST which can be imported in Outlook. It can import mailbox data from inaccessible, corrupt, encrypted and large OST files associated with Office 2019, 2016, 2013, 2010, 2007, 2003, 2002, 2000.


Import OST directly in Office 365

If you're planning to migrate mailboxes from your on-premises Exchange Server to cloud (Office 365), this OST to PST import software can help you make the transition easily. It extracts the mailbox data from OST file, which can be directly imported in Office 365. All you need is an Office 365 account with valid login credentials, and the OST to Outlook import utility relieves you from the tedious mailbox migration procedure.

*Free Download to preview the converted PST file and save 20 items per folder.

Why do you need to import OST in Outlook?

OST file is a synchronized copy or cache of user mailbox on Exchange Server, which is stored on the user’s local machine.OST file is a synchronized copy or cache of user mailbox on Exchange Server, which is stored on the user’s local machine. The OST file is bound to the specific Outlook mailbox profile on local machine and therefore not portable and cannot be opened anywhere out of that local machine, unless the associated mailbox profile is available. The OST file goes out-of-sync if Exchange Server crashes or in case if the user is unable to boot the local machine due to any reason. In this situation, the OST file and the mailbox data stored in it become inaccessible. In this case, the mailbox data is permanently lost if there’s no PST backup of the OST file.

Software Specifications

Operating System

Windows 10, 8.1, 8, 7, Vista, XP


Pentium Class


512 MB Minimum

Hard Disk

50 MB of Free Space

Single User License

Can use only on a single system

Technician License

Can be used on '3' Systems Simultaneously



Software Delivery



No, it is technically not possible to import OST file into Outlook. Outlook automatically creates an OST file when you add a new email account, and downloads mailbox data from server to the OST for offline use. The OST file is bound to the specific email account for which it was created. The OST file cannot be accessed if the associated email account is not available. In this case, the mailbox data inside the OST becomes inaccessible and you would need to use Stellar Converter for OST to import OST data in PST. The software converts OST file to PST file and extracts the mailbox data which can be imported in Outlook 2019, 2016, 2010, 2007, and older versions.

It is not possible to directly import OST file in Outlook different versions. In this case, Stellar Converter for OST can help import OST file into Outlook by converting the OST file into PST. The software extracts the mailbox data in PST format which can be easily imported in Outlook 2019, 2016, 2013, 2010, 2007, and 2003. The software can also directly import the OST file data in Outlook 365.

It is not possible to import old OST files directly into the latest version of Outlook: 2019, 2016. For importing old OST files, you would need to first convert the OST file into PST file by using the built-in Import/Export Wizard in Outlook. However, this built-in utility requires the associated email account for exporting OST file data. If the account is not available, then OST to PST Converter tool is the only solution to import OST in Outlook.

Outlook Import/Export Wizard is a tremendous utility to export mailbox data from OST file to PST, provided the OST-associated email account is available. The Import/Export Wizard cannot export data from OST for which the email account is not available. Another limitation of the utility is that it cannot work on corrupt OST files.

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