Using remote PowerShell to log into Office 365 and review archive mailboxes

I’m not much of an Office 365 expert but have recently had the opportunity to work with a client to migrate their on prem Exchange 2010 archive over to O365.  The process of deploying ADFS and DirSync was fairly painless but there seemed to be some confusion when I called into Microsoft Office 365 support where the support engineer did not understand why the migrated archived mailbox did not show up in the EAC (Exchange Admin Center).  To make a long story short, it was not until I worked with the third engineer when I was finally told it’s not to supposed to show up if the user’s mailbox is hosted on prem while the archive is hosted on Office 365.  The purpose of this post is for me to list the steps for reviewing the migrated archive mailboxes in case I need it again in the future.

The first step is to connect to Office 365 by launching PowerShell and execute the following:

$LiveCred = Get-Credential

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell/ -Credential $LiveCred -Authentication Basic -AllowRedirection

Set-ExecutionPolicy Unrestricted -Force

Import-PSSession $Session

Log in with your administrative O365 credentials:

You should see the following output once successfully authenticated:

Proceed an execute the following cmdlet to list a specific user’s archive mailbox:

Get-MailUser -Identity <userName@domain.com> |fl *archive*

Do not attempt to use the cmdlet:

Get-Mailbox -archive

… to list a user a user’s archive because it will not work when the user has an on prem mailbox with an O365 hosted archive:

To verify that the archive mailbox located on O365 is belongs to the on prem mailbox, compare the ArchiveGuid listed for the archive on O365 and the ArchiveGuid for the mailbox on the on prem mailbox by executing the following cmdlet:

Get-Mailbox -Identity <userName@domain.com> |fl *archive*

If you ever wanted to check whether a user’s archive is located on prem or Office 365, you can launch the Test E-mail AutoConfiguration option for Outlook, run the test, navigate to the XML tab and look for the <Type>Archive</T> tag that specifies the SmtpAddress as Office 365 rather than the internal on prem Exchange server:

To list all the archive mailboxes that are hosted on Office 365, execute the following cmdlet:

Get-MailUser | Where-Object {$_.ArchiveStatus -match "Active"} | fl DisplayName,*archive*