Regular/Shared mailboxes

Question

I am using Exchange 2016 hybrid environment. We create users on-premises and migrate them to online(some are created as remote mailbox from onprem). I have email addresses in a CSV file in the format below. I am using an M365 E5 license. I have 40,000 email addresses, and I suspect that 2,000 shared mailboxes are assigned M365 E5 license. I want to identify which addresses in the CSV file are shared mailboxes. Please guide me on how to import the CSV file, determine which addresses are shared mailboxes or regular mailboxes, and export the output to a CSV file. i have procured exchange online plan1 licenses and i want to assign those to the shared mailboxes and remoke M365 license.

email-list

user1@contoso.com

user2@contoso.com

Answer 1

Hi,

Welcome to the Microsoft Q&A forum!

You can follow these steps using PowerShell. Here’s a step-by-step guide:

1. Open PowerShell as an administrator.
2. Connect to Exchange Online:

   
       $UserCredential = Get-Credential
   
       Connect-ExchangeOnline -UserPrincipalName $UserCredential.UserName -Password $UserCredential.Password
   
   

3. Import the CSV file:

   
       $mailboxes = Import-Csv -Path "C:\path\to\your\file.csv"
   
   

4. Initialize an array to store the results:

   
       $results = @()
   
   

5. Loop through each email and check the mailbox type:

   
       foreach ($mailbox in $mailboxes) {
   
           $email = $mailbox.EmailAddress
   
           $mailboxDetails = Get-Mailbox -Identity $email -ErrorAction SilentlyContinue
   
           
   
           if ($mailboxDetails) {
   
               $isShared = $mailboxDetails.RecipientTypeDetails -eq "SharedMailbox"
   
               $results += [pscustomobject]@{
   
                   EmailAddress = $email
   
                   MailboxType = if ($isShared) { "SharedMailbox" } else { "RegularMailbox" }
   
               }
   
           } else {
   
               $results += [pscustomobject]@{
   
                   EmailAddress = $email
   
                   MailboxType = "NotFound"
   
               }
   
           }
   
       }
   
   

6. Export the results to a CSV file:

   
       $results | Export-Csv -Path "C:\path\to\results.csv" -NoTypeInformation
   
   

7. Identify Shared Mailboxes and update licenses:

   
       $sharedMailboxes = $results | Where-Object { $_.MailboxType -eq "SharedMailbox" }
   
       foreach ($sharedMailbox in $sharedMailboxes) {
   
           $email = $sharedMailbox.EmailAddress
   
           Set-MsolUserLicense -UserPrincipalName $email -RemoveLicenses "ENTERPRISEPACK"
   
           Set-MsolUserLicense -UserPrincipalName $email -AddLicenses "EXCHANGEONLINE_PLAN1"
   
       }
   

Answer 2

To know which email addresses in your CSV file are shared mailboxes and for managing their licenses, you can do this by powershell cmdlet. Follow the steps-

1.       Firstly, import the CSV file into Powershell

2.       Check if any email is a shared mailbox

3.       After that, export the result into the new CSV file

4.       For shared mailboxes, assign Exchange Online Plan 1 and remove M365 E5 licenses.