How curious! Outlook 2003 can’t read Exchange 2010 PSTs

Microsoft has released KB2742408 to report that Outlook 2003 clients can’t read PSTs generated by Exchange 2010’s New-MailboxExportRequest cmdlet. This is kind of curious, if understandable.

New-MailboxExportRequest is processed by the Mailbox Replication Service (MRS) running on a CAS server. It creates a PST in the newer Unicode format (rather than the older ANSI format originally used by Outlook to create its PST files) that should be accessible to Outlook 2003 as this was the first version of the client to support Unicode. Microsoft introduced the newer format to remove some of the problems that existed with ANSI files and to allow for PSTs larger than 1.9GB. I wouldn’t recommend that you create large PST files as I consider the format to be relatively unreliable, but they do seem to be much loved by some users.

No great detail about the reason behind the problem is offered in the KB article. It tells us that the reported error is:

“Unable to display the folder. Errors have been detected in the file “<file name>”. Quit Outlook and all mail-enabled applications, and then use the Inbox repair tool (Scanpst.exe) to diagnose and repair errors in the file. “

All this tells us is that Outlook 2003 has complained when it attempted to open the PST because it considers that some fundamental error is present. Running SCANPST.EXE in this instance is very much a “Hail Mary” pass as the program is unlikely to be able to repair deep-seated damage in a PST. I suspect that MRS has written something into the PST header that causes Outlook to barf; this is just a suspicion and I don’t have any great evidence to prove the point. Perhaps Exchange 2013 will solve the issue.

In the interim, all you can do is use Outlook 2007, Outlook 2010, or Outlook 2013 to open the PST and drag and drop the information from the file into a new PST – hopefully one that is consumable by Outlook 2003.

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About Tony Redmond

Lead author for the Office 365 for IT Pros eBook and writer about all aspects of the Office 365 ecosystem.
This entry was posted in Email, Exchange, Outlook and tagged , , . Bookmark the permalink.

4 Responses to How curious! Outlook 2003 can’t read Exchange 2010 PSTs

  1. Thomas Wallutis says:

    Hi Tony,

    i dont think that there is a real problem. Today we know that PSTs are evil;-) No one should use PSTs anymore. So there is no need to attach a PST to an Outlook 2003 client.



  2. Bert Leen says:

    I know about a tool to recover and repair pst file. Use Kernel for PST file repair tool help you to repair pst file and It supports both ANSI and Unicode formats of MS outlook.

    • Martyn Nash says:

      We have a scenareo where the Main HQ system is running Exchange 2010, and we occationally have to move people to a separate exchange system still running Exchange 2003. If we create a 2010 pst using the new-mailboxexport command, we find Exchange 2003 (exmerge) is unable to read the PST into the mailbox. We can do the other way round without any issue.

      Do you know how I can get a PST from 2010, that can be read by Exchange 2003. Our desktop is heavily locked down and Outlook can’t create or use PST’s.


      • Hmmm… New-MailboxExportRequest creates its output PSTs in the newer UNICODE format rather than the old ANSI format. However, “newer” in this context is relative because I think this format came in with Outlook 2003. I’m surprised that ExMerge cannot read the PST. I assume that Outlook can read the PST (one of the unlocked variety)? If so, maybe you could open the target mailbox and transfer the data that way… a bad solution, but the only one that comes to mind right now.


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