Audit-InactiveMailboxes

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#Get current date
$date = Get-date -Format MMM-dd-yyyy

#Number of days to substract from current date
$num = '-30'

#Set date to check last logon time
$lltdate = (Get-Date).AddDays($num)

#Find mailboxes with lastlogontime less than date provided, do not show null results and export to a CSV
Get-Mailbox -ResultSize unlimited | Get-MailboxStatistics | where {($_.lastlogontime -lt $lltdate) -and ($_.lastlogontime -ne $null)} | select DisplayName,lastlogontime | Export-Csv -Path C:\temp\MailboxAudit_$num-days_$date.csv -NoTypeInformation -Append


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#Import CSV of display names from previous step
$displaynames = Import-Csv -Path C:\temp\MailboxAudit_$num-days_$date.csv -Delimiter ','

foreach($displayname in $displaynames){

    #create new variable with for the name attribute filter
    $name  = "$($displayname.displayname)"

    #Search AD for accounts that match the filter criteria and export to csv
    Get-ADUser -Filter {(name -eq $name)} | select @{n="name";e={$($displayname.DisplayName)}},@{n="LastLogonTime";e={$($displayname.lastlogontime)}},samaccountname,userprincipalname,enabled |Export-Csv -Path c:\temp\MailAudit_$num-days_$date-Clean.csv -Append -NoTypeInformation

}


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#Import CSV of user returned from previous search loop
$UPNs = Import-Csv -Delimiter ',' -Path C:\temp\MailAudit_$num-days_$date-Clean.csv

foreach($upn in $upns){

    #Query Office365 and only return users that are showing as licensed. Out to a text file for further action
    Get-MsolUser -UserPrincipalName $upn.UserPrincipalName | where {$_.islicensed -eq $true} | select -ExpandProperty userprincipalname|  Out-File -FilePath c:\temp\MailboxAudit_UPNS-Licensed_$date.txt -Append

}