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Preparation of O365 servers by enabling IMAP access to mailboxes

Overview

When using LegacyFlo to migrate data from active mailboxes on O365, you will need to enable access to the mailbox. There are two methods to do this

  1. Using the GUI
  2. Using the Powershell

The first method is suitable when the data has to be migrated for a small set of mailboxes. To migrate data for a large number of mailboxes, Powershell can be used.

Enable IMAP access for Mailbox

Using Exchange Admin Center

  1. On the Exchange server open the Exchange Management Console.
  2. Under Recipient Configuration, click on Mailbox.
  3. Double click to open the mailbox user account.
  4. Open the Manage email apps settings.
  5. Select IMAP from the features list and then click the Enable button.

Using Classic Exchange Admin Center

  1. On the Exchange server open the Classic Exchange Admin Center.
  2. Under Recipient Configuration, click on Mailbox.
  3. Double click to open the mailbox user account.
  4. Open the Mailbox Features settings.
  5. Scroll down to the Email Connectivity section.
  6. Select IMAP from the features list and then click the Enable button.

Mailbox Delegation using Powershell 

  1. In the Microsoft 365 Admin Center, select Cloud Shell
  2. When prompted to choose between Console or Powershell, choose PowerShell
  3. Execute the Connect-ExchangeOnline command
  4. For each mailbox which needs to be enabled to access IMAP, execute the following command 
Set-CASMailbox <Alias, Primary SMTP, or UPN> -ImapEnabled $True
  1. When you need to enable IMAP access of 100s of mailboxes at a time, you can use Powershell scripts to filter and enable access
  2. Once the migration is over, you can remove the access using the following command 
Set-CASMailbox <Alias, Primary SMTP, or UPN> -ImapEnabled $False