Mailbox Usage

# Report on user mailboxes
.\get-mailbox-usage.ps1 -MailboxType UserMailbox
 
# Report on shared mailboxes
.\get-mailbox-usage.ps1 -MailboxType SharedMailbox

param(
    [Parameter(Mandatory=$true)]
    [ValidateSet("UserMailbox", "SharedMailbox")]
    [string]$MailboxType
)
 
# Output path - dynamically set based on mailbox type
$OutFile = ".\$MailboxType`Usage.csv"
 
$RecipientTypeDetails = $MailboxType
 
# Get only user mailboxes
$mbxs = Get-EXOMailbox -ResultSize Unlimited -RecipientTypeDetails $RecipientTypeDetails `
    -Properties DisplayName,PrimarySmtpAddress
 
# Get mailbox statistics in bulk for efficiency
# Note: Get-EXOMailboxStatistics doesn’t accept multiple identities at once,
# so we pipeline and select needed fields.
$results = $mbxs | ForEach-Object {
    $stats = Get-EXOMailboxStatistics -Identity $_.Identity
 
    # Calculate sizes in GB for readability
    $totalGB   = [math]::Round(($stats.TotalItemSize.Value.ToBytes() / 1GB), 2)
    $quotaGB   = $null
    $issueGB   = $null
    $prohibitGB= $null
 
    # Pull quota values from mailbox (these can be 'Unlimited' or sized)
    $issueQuota     = $_.IssueWarningQuota
    $prohibitQuota  = $_.ProhibitSendQuota
    $prohibitRecp   = $_.ProhibitSendReceiveQuota
 
    if ($issueQuota -and $issueQuota -ne "Unlimited") {
        $issueGB = [math]::Round(($issueQuota.ToBytes() / 1GB), 2)
    }
    if ($prohibitQuota -and $prohibitQuota -ne "Unlimited") {
        $prohibitGB = [math]::Round(($prohibitQuota.ToBytes() / 1GB), 2)
    }
    if ($prohibitRecp -and $prohibitRecp -ne "Unlimited") {
        $quotaGB = [math]::Round(($prohibitRecp.ToBytes() / 1GB), 2)
    }
 
    [pscustomobject]@{
        UserPrincipalName   = $_.UserPrincipalName
        DisplayName         = $_.DisplayName
        PrimarySmtpAddress  = $_.PrimarySmtpAddress
        MailboxType         = $RecipientTypeDetails
        TotalItemCount      = $stats.ItemCount
        TotalItemSizeGB     = $totalGB
        DeletedItemCount    = $stats.DeletedItemCount
        DeletedItemSizeGB   = [math]::Round(($stats.TotalDeletedItemSize.Value.ToBytes() / 1GB), 2)
        LastLogonTime       = $stats.LastLogonTime
        Database            = $stats.Database
        IssueWarningQuotaGB = $issueGB
        ProhibitSendQuotaGB = $prohibitGB
        ProhibitSendRecvGB  = $quotaGB
    }
}
 
# Export to CSV
$results | Sort-Object DisplayName | Export-Csv -Path $OutFile -NoTypeInformation -Encoding UTF8
 
Write-Host "Export complete: $OutFile"