The scenario. Recently, we performed an offsite Exchange rescue for a client who needed to retrieve the messages in the mailboxes of a legal firm. Our task was simple—send a tape back to the client with the individual mailboxes intact, which could then be bounced back to the server. I asked the client how many of the 94 mailboxes they wanted restored after we got the Exchange store restarted. “All of them,” the client replied. Suddenly, this task was not so simple.

I considered teaching my wife how to create the PST files so that we could take shifts, until common sense prevailed and I turned to the BackOffice Resource Kit (Second Edition, to be precise). Some care needs to be taken here. The simple version that appears in this Resource Kit has been superseded by far more advanced versions. In fact, Version 3.72 comes with a 60-page explanatory document.


ExMerge is not available as a download. To obtain the latest version, you’ll need to contact Microsoft Product Support Services.

What does it do?
ExMerge performs the task of copying messages from multiple mailboxes on an Exchange server into PST files, optionally copying them back into mailboxes on another Exchange Server—clearly perfect for our situation. Also, using ExMerge can save a large amount of time, as it can be left running without user intervention.

Preparations for using ExMerge

  • ExMerge will not run on a Windows 9x PC, so you will need a Workstation or server to run the utility.
  • Make sure that the account has Service Account Admin permissions on the site object you will be dealing with.
  • Make sure that you have the Exchange organization, site, and server names for the mailboxes you will be copying to and from.

Limitations of ExMerge

  • Inbox rules created on an Exchange 5.0 or later server will be copied, provided you use one of the later versions of ExMerge. However, Exchange 4.0 rules will not be processed.
  • Schedule+ data and forms will not be copied.
  • Single-instance storage will be lost, which might cause the information store to be significantly bigger on the server that the mailboxes are copied to.

A couple of warnings
ExMerge is simple to use, but you should be aware of a few issues:

  • Mailboxes that have been ExMerge’d may lose all their free\busy information. To work around this, create a profile to work on the mailbox. Open a command prompt and navigate to the directory where the outlook.exe program is located. Type outlook.exe /cleanfreebusy.
    Now, log on to the mailbox normally and check that the free\busy information is shown properly. Try scheduling a meeting for a time you know is already taken and check the attendee availability, which should show the time as busy rather than free.
  • You may find problems running the ExMerge tool on a PC that has Outlook 2000 installed. ExMerge may report that it could not read the list of recipients on the server. This is caused by different MAPI DLLs on the PC. There is a workaround in document Q250576. Basically, the procedure is to copy the mapi32.dll file from the \system32 folder of a computer with Outlook 98 installed to the folder where ExMerge is located.

ExMerge operation
ExMerge allows you to perform a one-step merge, which will copy the mailboxes into PSTs (named after the mailbox alias), copy the PSTs to another server and, optionally, delete the mailboxes when the copy operation is finished. Alternatively, a two-step merge allows the mailboxes to be dumped to disk and copied up to a different server at a later time.

The older Resource Kit version of ExMerge just has a filter that allows the selection of all the messages or messages created between two dates. But the latest version of ExMerge has a host of filter options. For instance, you could use ExMerge to delete a confidential message from an Exchange server by searching for a message by subject line.

When you’ve entered the organization, site, and server names, you can make additional selections, including the mailboxes to merge and where to put the PST files. The utility also creates a log file (exmerge.log) that lists any errors it encounters through its operation.

Back to the scenario
Within minutes, we had ExMerge installed, configured, and running. I got a good night’s sleep, and the courier had the tape in London at 14:00. The client simply bounced the contents of the PSTs into the mailboxes on the running server and history was restored.
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