Outlook 2016 .- ost file issue

kurajesh used Ask the Experts™
I have an .ost file saved as outlook.ost and while attaching this as a data file to a profile it says "File you chose is not and outlook data file and I have scanned this file using scanpst.exe and repair was completed, Still same error occurs while attaching this file

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IT Engineer
Distinguished Expert 2017
You can't attach OST file to outlook.
Only PST file are allowed to attach to Outlook.

Ost is automatically created when Active Synch connection is set for the first time and is bonded to profile.
If you need to attach old emails you must convert OST to PST first

You can use Microsoft converter from here

Tom is correct you can't open .OST as outlook data file.  it is offline outlook data file.

Read following article to understand the deference between OST and PST

Sandeep KumarAssociate Consultant

As of now, you are aware that OST email can be imported to Outlook. Then for same need, you can either refer to the manual method to convert OST file to PST or refer to third party tools.

To manually migrate OST file to Outlook PST, visit: http://expert-advice.org/microsoft-outlook/convert-ost-file-to-pst-file-manually/

For automated tool, Use Kernel for OST to PST converter tool.
Visit: https://www.nucleustechnologies.com/ost-to-pst-converter.html to download demo software and know more about its features.
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OST file is bound to its original MAPI profile, hence one cannot access, open and attach its content outside of its original MAPI profile in which it has created. If you have access to the original MAPI profile then you can use Export option of Microsoft Outlook to export OST file in Outlook. But if your OST is orphan then you have only one option left is to use any reliable Convert OST to PST utility.
david adwardSupport Engg

you must be thinking that how to import this process of OST file to fixable Outlook 2016?

See the below section where we have mentioned manual as well as an automated OST to PST migration solution for the same or refer to 3rd party tools.

To manually Export OST file to Outlook: http://expert-advice.org/microsoft-outlook/convert-ost-file-to-pst-file-manually/

For use KDETOOLS for OST to PST converter tool.

FREE download demo ost to pst program and know more about its features.
Lucas DawsonTech Reviewer


Agreed with other experts, till now you must be known that you can't attach your OST files directly to MS Outlook profile. You need to convert your OST files into PST format and then import them into Outlook. I will recommend you a free Microsoft recovery cum converter tool to download and try its free version, if it suits your situation then you can proceed for the purchase option.

Brian BEE Topic Advisor, Independant Technology Professional
Can you still access the Exchange server?

Most of the tools recommended you have to buy to get any results. You probably don't need to do any conversion at all. If you still have a connection to the Exchange server, just set up a new profile in Outlook and it will synch to the server and create a new OST file.
OST file is unable to directly import in Outlook. Outlook supports only PST file. So, first convert OST to PST format and then import this PST file in Outlook.  https://filehippo.com/download_vmail-ost-to-pst-converter/

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