We have migrated almost all of our mailboxes from Exchange 2003 to 2007 so both are still up and co-existing in our domain. One mailbox is missing some mails, and I tried to recover from an Exchange 2003 backup using ExMerge as usual, but it throws an error: Error opening message store (MSEMS). Verify that the Microsoft Exchange Information Store service is running and that you have the correct permissions to log on. (0x8004011d)

This should be normal when a mailbox has been migrated to 2007 and you try to recover a 2003 backup as stated here: http://www.petri.co.il/restoring-exchange-2003-mailboxes-exchange-2007-exmerge.htm

We then tried the solution given in the article (copying the value "homemdb" for the user and pasting this in "msExchOrigMDB" for the Recovery Storage Group object in adsiedit). The error unfortuntely persists.

So my question is, how can I extract a .pst from a mailbox in the recovery storage group when both Exchange 2003 and 2007 are running? I assume this is why the solution in the article didn't work.

If no solution is possible using regular tools (exmerge, eseutil, etc.) which third-party tool should we choose - preferably the cheapest as we only need this one mailbox recovered.