The horrors of migrating to Domino when Single Item Recovery is in use on Exchange

Here's a new one for ya, true believers.

The past couple of weeks I have been involved with migrating email users from a recent acquisition my company made to Domino from Exchange.  This is a process I have done many times in the past and when using CMT from Binary Tree, it's a very straight forward but drawn out task. However, this time posed a bigger challenge. One that I have never encountered before.  And it was a pain.

Like migrations in the past, I've relied on someone who understands the dark arts of Exchange to supply me with a .PST copy of the mail files for each of the users.  This migration was no different and I had a support person on site do that for me.  But after migration was done, I was getting a lot of reports that peoples calendars were all buggered up.  Upon investigation, I looked at a users Notes calendar and saw something similar to this:

Ya.  That doesn't look right, does it?

But when I opened their .PST file in Outlook, those repeating calendar items were only in there once.  I also noticed that in the .PST files, there were also folders called "Recoverable Items".  Have never seen that before in my migrations, it was off to the interwebs!  After consulting Google, I found the answer.  The Exchange server was set up to use Single Item Recovery, (you can read more about it here. The more you know!).  In Exchange, Single Item Recovery is a function that allows users to delete and edit things in their mail file while keeping a copy of everything they do tucked away in a "dumpster".  As what normally happens with calendar entries, there were a lot of edits to those repeating meetings, so when the onsite tech person did a standard migration to a .PST it included all of the "dumpster" data with it.  When CMT opened the .PST and started the migration tasks, it saw the information in those Recoverable Items folders and acted upon it like any other data, hence all of the deleted emails and calendar entries were merged into the Domino mail file and caused a mess.  Harrumph.

Luckily, CMT has a great function that keeps track of all the migrated items and will remove them from Domino if needed.  I had to go through and do that for all those users.  I then posed the question to Binary Tree if there was some way to do the migration without migrating anything in the Recoverable Items folders but was told that it can't.  CMT will do anything in the .PST.

So after some more Googling, the team found the the magic key.  The .PST's needed to be generated with the following Powershell command.

New-MailboxExportRequest -Mailbox UserName -ExcludeDumpster:$True -FilePath \\filelocation\UserName.pst

Once my onsite person migrated the Exchange data to new .PST files, they now didn't contain that "dumpster" data and were then migrated into Domino just fine.  Whew.  

So if there is ever an instance in my future where I have to migrate a .PST to Domino, the first question I'm going to ask is is Single Item Recovery is in use.  And if there is ever an instance where you have to do a migration, never overlook this either.