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You can convert an .ost from Outlook 2003 to a .pst by copying its contents into a new .pst file, but you must be able to open the .ost.

How can I convert an .ost from Outlook 2003 to a .pst file? I have tried ost2pst.exe, but it does not support 2003.

Well, to begin with, there is an (expensive) program called Exchange Recovery 2.0 that claims to handle the new 2003 file formats.

If you can open the OST file in off-line mode, you can then create a PST and simply copy the contents of the OST over to the PST. The trick here is opening the OST at all since it is typically tied to a specific profile or Exchange Server account settings. If that account is not available, then you may not be able to open the OST.

A Google Search for "OST PST conversion" returns several companies that provide for-fee conversion services.

Article C2078 - June 22, 2004 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

November 4, 2004 11:24 AM

I am trying to transfer .pst file (ms outlook)from an old 98 to xp version. How do I do that??


November 4, 2004 9:15 PM

Just copy the file over and open it in Outlook on the new machine.

February 3, 2005 1:41 AM

My exchange 2003 failured and i had to re-install it,TRIED to restore the mail box into the new exchange but failed.Fortunately .ost file is available with my old emails.Now i want to import the same into my inbox, do i go about?

February 3, 2005 4:49 PM

Hi Mugesi

What you do is take a look at the service I provide at or e-mail me at (remove NONOSPAM).

I can take your ost file and convert to a pst.



March 24, 2005 10:28 PM

How can i convert a .ost file from outlook 2000 & 2003 to a .pst file?

March 24, 2005 10:30 PM

I would creat an empty PST, open both the OST and PST in Outlook, an drag/drop the contents from one to the other.

July 3, 2005 11:44 PM

open in ost and export it to pst...then connect to the exported ost which would be in pst format.

November 24, 2006 1:22 AM

The easies way to open your .ost file on outlook is to export your mail account to a .pst file. You can open the file on other outlook applications.

Rajesh Raman
April 21, 2007 2:37 AM

I tried a lot to recover my ost files. But i really fedup for one day. After all when i am searching internet for a solution i got this link to your web page. I succeeded in the opertion. I am thanking this site for the kind information.
Thanks a lot.

Rajesh Raman
Technical Executive
Vinirma Consulting Private Limited.

June 28, 2007 9:10 AM

I just recovered an Outlook 2003 .ost by converting it to .pst using the stellar phoenix demo program which was linked to above. Definitely helped me dodge an IT bullet.

September 9, 2007 7:47 PM

P.S. if you need to open a .rar file for god's sakes use 7-zip not some trial version POS like WinRAR

May 26, 2008 9:51 AM
I'm closing comments on this article because the majority have been thinly veiled product advertisements posted by various recovery and conversion utility producers. I have removed those. (Sorry if I removed legitmate posts from real people with real recommendations, but this was turning into an ad-fest.)
If you want to advertise, please see this page: Advertising on Ask Leo!
- Leo

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