Domino to O365 Migration|Shared Mailbox Sent Items

Domino to O365 Migration of Mailin Databases

For a typical Domino to O365 migration, migrating mailin databases to Shared Mailboxes can present many challenges.   How Sent Items are treated is a good example.   In Domino if you work with a mailin database, then Sent Items are kept with that mailbox.  Once the mailin database is migrated to Office 365, it can be converted to a Shared Mailbox, which is a good idea, as no licence is consumed.  You then grant the user delegate access to the Shared Mailbox (Full Access and Sent As).

Mailin Database converted to Shared Mailbox Issue

However, when the user sends a mail “from” the Shared Mailbox, the mail item goes to the user’s Sent Items folder, not the Shared Mailbox.   This is very annoying, and may have compliance issues.  Thankfully, Microsoft have provided a new feature in Office 365 that allows this behaviour to be changed.

Azure Powershell Solution

You can use Azure Powershell to set the Sent Item to be copied to both the user Sent Items Folder and the Shared Mailbox’s Sent Items Folder.

The two cmdlets to enable are:

Set-Mailbox <delegator mailbox name> –MessageCopyForSendOnBehalfEnabled $true

Set-Mailbox <delegator mailbox name> -MessageCopyForSentAsEnabled $true

And to disable, the two cmdlets to enable are:

Set-Mailbox <delegator mailbox name> –MessageCopyForSendOnBehalfEnabled $false

Set-Mailbox <delegator mailbox name> -MessageCopyForSentAsEnabled $false

I used these cmdlets for my project:

get-mailbox shared1 | set-mailbox –MessageCopyForSendOnBehalfEnabled $true

get-mailbox shared1 | set-mailbox -MessageCopyForSentAsEnabled $true

The full Microsoft article is here as reference:


I am glad that Microsoft has provided this feature, as this makes life a bit easier for my Domino to Office 365 migration projects that I consult on.  If you need help with your Domino to O365 migration, please get in touch!

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