Recently I was trying to import some PST files to an Exchange 2003 server using ExMerge. The PST files had been collected from clients that had previously been running POP3 accounts using various versions of Outlook. The import was part of a migration process where we moved from these POP3 accounts to Exchange 2003. Earlier we upgraded all clients to Outlook 2003 and created profiles for Exchange. Although all the clients were running Outlook 2003 now, some PST files had been created with previous versions of Outlook and some with Outlook 2003. As it turned out, this was a problem.

Upon starting the import job I immedialey started to get failures in ExMerge. This was unusual since I had verified all the PST filenames and made sure they matched the mailbox name in the Exchange database. I exmained the ExMerge log and found these errors:

Merging data from file ‘E:EXMERGEDATAUSER.PST’ to mailbox ‘User’ (‘USER’) on server ‘SERVER1’.
Error configuring message service (MSPST MS)(MAPI_E_EXTENDED_ERROR)(CMapiSession::CreateEMSPSTProfile)
Errors encountered. Copy process aborted for mailbox ‘User’ (‘USER’).

I had never seen this particular error before so I started to investigate.

After some research I found out that Microsoft changed the format of the PST and OST files in Outlook 2003 to eliminate the problems with the 2GB limits on these files that the previous verions of Outlook were hampered by. The new Unicode PST/OST files can be up to 20 GB and are in Unicode by default. The older versions of Outlook user ANSI. If you want to know more about this feature I suggest the fillowing links:
http://support.microsoft.com/kb/830336/
http://support.microsoft.com/kb/832925/

Combining this information with the error from the ExMerge log (CreateEMSPSTProfile), I guessed that maybe ExMerge could not read this new Unicode format. This was indeed the case, as the Knowledge Base article 823176 proved:

“The ExMerge utility does not support Unicode .pst files. If you export data from Outlook 2003, the default .pst format is Unicode. To work around this issue, create an ANSI .pst file. This is a .pst file that is compatible with Outlook 97 and with Outlook 2003.”

Here is the link to the article if you want to read all of it:
http://support.microsoft.com/kb/823176

The only soultion left to me in this case was to manually convert the new Unicode PST files to ANSI PST files. This was a very tedious process, that had to be done with Outlook 2003. First creating an ANSI PST file and the importing the Unicode file, and finally importing that file with ExMerge into the Exchange store. I could not find any utility to do this automatically or one to convert the file. Luckily for me there were only a few files out of the total that had to be converted.

The reason that I write this blog post is partly to share an interesting discovery with my peers, but also beacuse the error that ExMerge logs (CreateEMSPSTProfile) is not documented anywhere as being caused by an Outlook 2003 Unicode PST file. I think that it should be and so I blogged about it here. Hopefully Google will index this post soon and it will be available when someone has the same problem as I did.