Office365: How to properly restore Archive-Data and disable an Archive-Mailbox

In His article Maor describes the steps required to properly disable an archive mailbox while maintaining related data.

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Hello Office365 pros.

Recently I’ve been asked by several of my clients: “What happens to an Exchange Online Archive-Mailbox data once it’s disabled?”
To answer that question, I would quote the following TechNet article:
“Disabling the personal archive will remove the archive from the mailbox and mark it in the mailbox database for deletion. If you disable a personal archive, all information in the archive will be kept in the mailbox database until the mailbox retention time passes and the personal archive is permanently deleted. “

Hence, in all Exchange versions, disabling an archive mailbox would not merge the archive data back to the user mailbox, but rather flag it as a disconnected mailbox.
This might be OK when dealing with Exchange On-Premises, as the techies are able to control retention policies and use various ways of retrieving the data in question.
However, while disabling Office365 Exchange-Online archive mailboxes, you might want to plan ahead and make sure you do it correctly in order to keep your data safe and your users satisfied.

So, in order to overcome this difficulty-

Following are the recommended steps to restoring Archive-Data and disabling an archive-mailbox:

1. Create a new retention policy, which excludes data archiving or temporarily assign “No Policy”:
As you may know, Exchange offers control over the retention policies and tags.
It is recommended to start by creating a new retention policy, which excludes archiving tags or temporarily assign “No Policy”- in order to make sure your data is not re-archived during the process.
This can be done by either browsing to Recipients>Mailboxes>Edit Mailbox>Mailbox Features>Retention Policy, Select “No Policy” and click “Save”.


2. Restore Archive-Mailbox data to the main mailbox:
For this step we need to identify our user: are we revoking an archive mailbox from an otherwise working user, or is this a user that is no longer working (for instance, a user that is no longer employed in the organization)? For the latter, you can skip to step #4 and continue with the tasks described in section 2.B. in order to complete the process.

2.A. Seamless merge preperations:

In this article we would use “New-MailboxRestoreRequest” in order to easily restore archive data back to the primary mailbox, while allowing our user full archive data access in the process. However, running this command is only possible against disconnected mailboxes.


This could pose an issue when we’re dealing with live users which require constant access to their data.

So, how do we get around it?
I found out that you can “trick” Exchange servers into allowing this command by disabling the archive, and then enabling it again. This would actually disconnect the archive and reconnect it, allowing us to run the command but with no user impact.

Use the following commands in order to disable and enable the archive mailbox:
Disable-Mailbox –Archive –Identity <Primary SMTP Address>
Wait for ~10 seconds.
Enable-Mailbox –Archive –Identity <Primary SMTP Address>


Important note:
You may notice, disabling an archive mailbox is basically the same command as disabling a primary mailbox with the addition of the “-Archive” switch – So please, pay attention.

2.B. Restore archive data into the primary mailbox:

Use the following command in order to restore the data back to the primary mailbox

New-MailboxRestoreRequest -Name <Mailbox Name> -SourceMailbox <Mailbox Primary SMTP> -SourceIsArchive -TargetMailbox <Mailbox Primary SMTP> -TargetRootFolder <Destination Folder>


As mentioned, the user still has archive access during the process.
Monitor the restore request by using:
Get-MailboxRestoreRequest –Name <Mailbox Name>


3. Verify data integrity:
Once the mailbox restore request shows completed (as shown above), you will be able to see the restored items in the destination folder specified earlier.


A further inspection would be to use PowerShell commands to cross examine archive folder statistics and restored items statistics.

Using the following command would return the folder names and sizes in the archive mailbox:
Get-MailboxFolderStatistics -Identity <Primary SMTP> -Archive | FL Name, FolderSize, FolderAndSubFolderSize
For instance:


To get restored items statistics, use the following command:
Get-MailboxFolderStatistics -Identity <Primary SMTP> | Where {$_.Name –Like *<Folder Name>*} | FL Name, FolderSize, FolderAndSubFolderSize


*Notice: The Archive-Mailbox “Top Of Information Store” would be represented by the folder name in the primary mailbox, as shown above.

4. Disable Archive-Mailbox:
Once the restore request is complete and the data integrity is verified, we can safely disable the Archive-Mailbox.
Browse to Recipients>Mailboxes>Edit Mailbox>Mailbox Features>Archiving, Select “Disable”.
If you assigned a different retention policy on step #1, you can also revert the change to the original policy.
Don’t forget to click “Save” to apply changes.



Maor Bracha

About the Author

Maor Bracha - Integration Team Leader at U-BTech Solutions

Maor works as Integration Team Leader at U-BTech Solutions. As part of his job, Maor leads projects in Microsoft Exchange, Office 365, and Active Directory for leading companies.

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