Script to connect to Office 365 and collect the last logged on date/time, mailbox size and item count for each mailbox and archive mailbox for every user within your organization.

The following script was specifically written for a client recently which I thought would be good to share with the wider community. This will connect to Office 365 and collect the last logged on date/time, mailbox size and item count for each mailbox and archive mailbox for every user within your organization.

Those users without an archive mailbox will be returned as ‘No Archive’

For more information about this script please see the source at: https://gallery.technet.microsoft.com/scriptcenter/Find-Mailbox-and-Archive-2859b540

$Office365Credentials = Get-Credential
$session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri "https://ps.outlook.com/powershell/" -Credential $Office365Credentials -Authentication Basic -AllowRedirection
Import-PSSession $session
 
Write-Host "Gathering Stats, Please Wait.."
 
$Mailboxes = Get-Mailbox -ResultSize Unlimited | Select UserPrincipalName, identity, ArchiveStatus
 
$MailboxSizes = @()
 
foreach ($Mailbox in $Mailboxes) {
 
                $ObjProperties = New-Object PSObject
               
                $MailboxStats = Get-MailboxStatistics $Mailbox.UserPrincipalname | Select LastLogonTime, TotalItemSize, ItemCount
               
                Add-Member -InputObject $ObjProperties -MemberType NoteProperty -Name "UserPrincipalName" -Value $Mailbox.UserPrincipalName
                Add-Member -InputObject $ObjProperties -MemberType NoteProperty -Name "Last Logged In" -Value $MailboxStats.LastLogonTime
                Add-Member -InputObject $ObjProperties -MemberType NoteProperty -Name "Mailbox Size" -Value $MailboxStats.TotalItemSize
                Add-Member -InputObject $ObjProperties -MemberType NoteProperty -Name "Mailbox Item Count" -Value $MailboxStats.ItemCount
               
                if ($Mailbox.ArchiveStatus -eq "Active") {
               
                                $ArchiveStats = Get-MailboxStatistics $Mailbox.UserPrincipalname -Archive | Select TotalItemSize, ItemCount
                               
                                Add-Member -InputObject $ObjProperties -MemberType NoteProperty -Name "Archive Size" -Value $ArchiveStats.TotalItemSize
                                Add-Member -InputObject $ObjProperties -MemberType NoteProperty -Name "Archive Item Count" -Value $ArchiveStats.ItemCount
 
                }
                else {
               
                                Add-Member -InputObject $ObjProperties -MemberType NoteProperty -Name "Archive Size" -Value "No Archive"
                                Add-Member -InputObject $ObjProperties -MemberType NoteProperty -Name "Archive Item Count" -Value "No Archive"
                               
                }
               
                $MailboxSizes += $ObjProperties
 
}             
               
$MailboxSizes | Out-GridView -Title "Mailbox and Archive Sizes"
 
Get-PSSession | Remove-PSSession