.OST file problem

Copper Contributor

My pc died, but I had saved my .ost file.  I wasn't able to export my contacts from outlook.  I use Gmail with imap settings.  I installed Outlook 2021 on the new pc and connected to my gmail account and all the mail was downloaded. Now I'm unable to swap the old .ost file with the newly created one to export  my contacts and import to outlook.

Is there anyway I can extract my contacts from the original .ost file and import to outlook?

Or is there anyway to change the .ost file to .pst, then I can load the .pst file in outlook to export the contacts and import them to the new .ost file within outlook?

Thank you.

9 Replies


Thank you for responding. However, a new ost file was created when I loaded Outlook 2021 and connected to my gmail account.  All my mail downloaded at that time.  I closed outlook, moved the new ost file to another location and put the old ost file in it's place.  When I launched outlook, it gave an error to the effect that it could not connect the ost file to gmail since the ost file was configured to a different account. I tried various things to get around this to no avail.

Hence, I'm stuck without anyway to open the original ost file and export my contacts.

That being the case, your only option, at this point, is a third party tool such as the one kelvinmarkus suggested. Here's another one:


@Hal Hostetler 

Hal, I bought a converter which successfully extracted my contacts to a .pst.  However, when I go to add the .pst via File, Account Settings, Data Files, Add, I get this error when selecting Outlook data file (.pst): 

 An unknown error occurred, error code: 0x80070002.  I can't get past that to even select my pst file.  I did a full repair on Office 2021 and continue to get the same error. Researching that error did not yield any usable solutions.  

At this point, I'm stumped.


That error often means there is an issue with the .PST file. Have you tried running the Inbox Repair Tool (Scanpst.exe) on the .PST file? Instructions are here:

Using the Inbox Repair Tool (scanpst.exe)

More info on the error is here:

An Unknown Error Occurred Error Code 0x80070002 in Outlook

I get that error when I get to the New Outlook Data file window box. I then highlight Outlook data file (.pst). As soon as you click Ok, the error comes up. You don't even get a chance to browse to your data file. The same error pops up when you select iCloud from the window. Truly bizarre.
Hal, I resolved the problem. Instead of trying to add a data file, instead I did a file import. That brought in the whole pst so I simply opened the contacts, copied and pasted them to the correct contacts for my mailbox and all is now right with the world. What a time consuming effort. Thanks again to you and others who responded. Be well.



Thank you. I used another ost to pst converter to resolve the issue. Thank you.

I will recommend users to use MailsDaddy OST to PST Converter which allows users to recover the corrupted OST file and export them into PST format. Here users can also save OST files contact into CSV/VCF and calendar details in ICS format. Here users can also convert OST files into EML, MSG, MBOX, RTF, Office 365, Live Exchange Server, and others.
To know more, visit here: https://azuremarketplace.microsoft.com/en-us/marketplace/apps/mailsdaddysoftwarepvtltd1638009988606....

OST file problems can be terrible for non-technical users. Most other account types, such as IMAP accounts, Microsoft 365 accounts, Exchange accounts, and Outlook.com accounts use an Offline Outlook Data File (.ost) file to store a synchronized copy of your mailbox information on your local computer. If you want to free the OST files problem then use the TrustVare OST to PST Converter Software to safely export exchange server files to Outlook PST file format without losing any single file. There are users who no need to install other software to convert OST to PST. If users want to see more features and capabilities of the app then they can download the free demo version of this app without giving single money.

Read More: https://www.trustvare.com/ost/pst/