Before you prune previous participants, it’s propitious to preserve their publications in a pst.
OK, alliteration aside, it’s really easy to kick out a pst file from a user’s Exchange 2007 or later mailbox before you delete them.
First you need to share a folder somewhere, the cmdlet needs a UNC path to export to. This can be a local folder on your exchange server. The group “Exchange Trusted Subsystem” needs read/write access to this folder.
Then, pop open your exchange management shell and run:
New-MailboxExportRequest -mailbox theUserId -filepath \\theServer\theShare\thePstFileName.pst
This will export the mailbox “theUserId” to the “theShare” folder on “theServer“
You can run this again for each user you want to export. This will queue the exports up and you can see the status by running:
and clear the completed ones with
Get-MailboxExportRequest -Status Completed | Remove-MailboxExportRequest
Now you have a nice backup pst and can safely remove that mailbox from your mailbox store 🙂