IMAP migration to Office 365 step by step guide

IMAP migration to Office 365

The easiest way to migrate your mailboxes is through IMAP (Internet Message Access Protocol). Luckily, Google supports IMAP for non-Gmail users. IMAP migration to Office 365 can only work with admin access, so you must have admin credentials with access to user passwords.

Steps to Mailbox Migration

  • Verify the domain you own which is already connected to your Google Business Account. You also have the option to create a domain as part of your Office 365 setup. 
  • Create users in Office 365 and assign licenses to begin the migration process
  • Create a list of mailboxes to include in the migration. You can create this CSV file in Excel with the original Gmail address, Office 365 email address, and passwords, which are temporarily assigned. 
  • Connect your Microsoft 365 account with Gmail. This can be done from the Exchange Admin center. Go to ‘Recipients> Migration> More…’ and set the Migration endpoint. Make sure to select IMAP as the endpoint type.
  • For IMAP migration configuration, leave the default settings as is. The IMAP server for Gmail is listed as “” 
  • Begin the migration process. You can do this in batches or all at once. 

IMAP migration to Office 365, step by step process

  • Open the Exchange Admin center.
  • Under the ‘Recipients’ tab, select ‘Migration.’
  • Under the IMAP migration that you set in the previous step, click next. This will take you to the “Select Users” page. 
  • Click Browse and select the CSV file. Verify the number of users to be imported. You can also try a test batch of a few users before migrating the rest. 
  • Select the migration endpoint already created in the next step and move on to the “Move configuration” section.
  • Add names to your batches for a more straightforward process. You can also add folders that do not need to be imported (such as Trash or Spam).
  • Click on “Start the batch” and select “Automatically start the batch.” This will begin the mailbox migration process. 

You can check to ensure the migration process has started from the Exchange admin center. Under the ‘Recipients’ tab, select ‘Migration’. From here, check that the batch name you assigned to the migrating batch is showing the ‘Synced’ status. 

Once migration is complete, users should be able to access their new accounts with the temporary password, which they should reset.

Change DNS Record

The Mail Exchanger (MX) record on the DNS is responsible for identifying where to route emails to a domain name. This needs to be switched from Gmail to Microsoft so that the newly set up accounts can start receiving their mail. 

  • Open the Microsoft admin center
  • Under ‘Show All’, select ‘Settings’ and then ‘Domains.’
  • Sign in to your DNS provider
  • Open your settings manager
  • Add the MX record from the admin center to your domain

This process can take a day or two to come into full effect. Because of this, it is best to wait a few days and ensure all mail is being sent and received correctly before removing old Gmail accounts.

Once you have ensured everything is working as it should, you can stop the synchronization process. You should delete the Migration batch from the Exchange admin center following the completion of the process. Once you do this, old Gmail accounts will no longer be accessible. 

Interested in having even more details? Read this article about Migrating Gmail boxes to Microsoft 365

If you have any questions about IMAP migration to Office 365, Contact us, Wintellisys is always happy to help!

About the Author Anton Tverdokhlib