How to Migrate IMAP Emails to Office 365? – Expert Guide

Summary: IMAP email accounts are most popular among businesses as they are most often provided with your domain name. Moreover, it enables you to use your custom domain email address. However, because of advanced functionalities, enhanced security, and numerous services, most businesses prefer Office 365 accounts over their IMAP email accounts. So, they want to migrate IMAP emails to Office 365 accounts.
Here we will share the manual method in detail to perform the migration process. You can use the IMAP Mail Backup Tool to make this process quick and easier.

What Leads to IMAP to Office 365 Migration?

Almost every email provider supports IMAP servers. You can enable IMAP in your Gmail email account. However, IMAP email accounts with custom domains can be accessed via Roundcube, Horde, etc. They offer limited features and a very basic GUI that is only suitable for sending and receiving emails. On the other hand, Office 365 provides numerous advantages over IMAP accounts.

  • Office 365 is a cloud Office Suite that provides you with all the Microsoft productivity applications like Word, Excel, PowerPoint, Outlook, OneDrive, Exchange, etc.
  • It is fast and effective and allows you to manage your business efficiently.
  • Office 365 offers a more secure and robust mailing solution.
  • You can also manage your appointments and important events with Calendars.
  • Backing up and migrating your mailbox will be easy with an Office 365 account.

Because of all these reasons, users want to migrate IMAP Emails to Office 365 accounts.

Measures to be Taken While IMAP to Office 365 Migration

The manual method to migrate IMAP emails to Office 365 accounts is quite tedious and complicated. Moreover, there are certain points that you need to keep in mind before you start exporting your IMAP mailboxes to Office 365 email accounts.

  • If the Messaging Record Policy (MRM) or archival policy is enabled, you may be unable to find some of the emails. This functionality might move your emails to the archive folder and flag them as missing.
  • This procedure has a limit of migrating a maximum of 500000 emails from user mailboxes.
  • The largest email size you can migrate through this approach is 35 MB.
  • You can only migrate IMAP emails through the manual approach. You can not migrate contacts, calendars, or any other Office 365 item.
  • You must first create users in an Office 365 account before initiating IMAP to Office 365 account migration.

Complete Manual Procedure to Migrate IMAP Emails to Office 365 Account

The manual method to migrate IMAP to Office 365 account is quite complicated and involves multiple stages. You need to perform every step in the sequence to successfully migrate your mailbox data. Apart from that, you must fulfill some prerequisites before migrating emails.

IMAP to Office 365 Migration Prerequisites

  • First, you must add your IMAP domain to the Office 365 account. It will enable Office 365 to import emails from another email address.
  • Creating user mailboxes in the target Office 365 account is necessary because you have to provide an appropriate destination for every IMAP user account.

#1: Identify Server Settings of your IMAP Account

For migrating your IMAP to Office 365 email account, you must know the Incoming and Outgoing server settings of your IMAP email account. You can not initiate the migration without knowing the server settings. This detail is available on Google. Alternatively, you can identify these details from your IMAP account.

#2: Create a File of IMAP Accounts Credentials

The second step is to create a CSV file containing the login details (Username, Email Address, and Password) of the source IMAP email account. This file helps you to access source IMAP user mailboxes. So, you can easily add IMAP emails to Office 365 Account.

Open Notepad and type the email address, username, and password of every IMAP user account separated by commas without any space. Details of each mailbox should be written in a new line. Now, save the file with .csv at the end.

#3: Connect IMAP Account to Office 365 via Classic EAC

Migration Endpoint is a functionality in Office 365 that is mainly used to connect other email accounts to the Office 365 account. To migrate from IMAP to Office 365, you need to create a migration endpoint.

  • Log in to your Office 365 account. Go to the Admin option and select Exchange.
  • Select the Exchange Admin Center option and choose the Recipient option.
  • Then, click on the Migration option. Press the More button and choose Migration Endpoint.
  • After that, press the Add button (+ icon) to create a new migration endpoint.
  • A pop wizard will appear. Click on the IMAP button and provide a suitable IMAP server name.
  • After successfully connecting to Office 365, you will see a general Information page of Migration Endpoint.
  • Provide the desired details of the Migration endpoint and hit the New button to create the Migration Endpoint.

#4: Create a New Batch for Migration

In this step, we use the CSV file created earlier that contains all the desired user mailboxes for conducting migration in bulk. Below are the steps to create a new batch for migration.

  • In the Exchange Admin Center, select the Recipient button.
  • Press the Add button and choose the Migrate to Exchange online option.
  • After that, choose the IMAP Migration option and press Next.
  • A pop-up will appear. Click the Browse button and choose the CSV file.
  • All user accounts will be displayed on the screen. Validate and press Next.
  • You will see the IMAP Migration Configuration page. Press Next to proceed.
  • After that, select the newly created Migration Endpoint.
  • Provide migration batch name and click on the Next button.
  • Now, the migration batch has started.

#5: Mailbox Routing to Office 365 Account

For migrating your IMAP emails to Office 365 account, you need to point the DNS records to the IMAP email account as they should be directed toward the source email account. After completing the migration process, it is mandatory to point them to the Office 365 account.

After migrating all your IMAP mailboxes to your Office 365 account, you need to delete the migration batch you created. It will stop the synchronization of your IMAP account with the Office 365 account.

It is the complete manual procedure to transfer IMAP emails to Office 365 accounts without using any third-party tool. As you can see the process is too lengthy, time-consuming, and complicated. So, if you are a novice user, we would never suggest this approach for migrating your mailbox data to the Office 365 account. We recommend the best professional IMAP Backup Tool.

Best Alternative to Export IMAP Emails To Microsoft 365 Admin Center

The best way to migrate IMAP emails to Office 365 accounts is the professional  MigrateEmails IMAP Backup Tool. It is a complete solution for migrating any IMAP-enabled email account whether it is Gmail, Yahoo Mail, or any custom domain email account. You can export multiple IMAP accounts simultaneously with the Import CSV file option. Also, the application enables you to migrate IMAP to Google Workspace, Gmail, Office 365, and another IMAP account. The application has numerous advanced features and is widely compatible with all versions of Windows OS.


To easily migrate IMAP Emails to Office 365 account, you need to perform a set of procedures in the correct sequence. First, find out the incoming and outgoing server settings and then prepare a CSV file of IMAP accounts. After that, connect your IMAP account with Office 365. Then, you will have to create a migration batch and at last, route the mailbox. After you migrate your IMAP mailbox to Office 365, you need to point DNS toward Office 365 and delete the migration batch.

Frequently Asked Questions

What are the limitations of IMAP migration?

Migrating an IMAP account to Office 365 has various limitations.
•Your emails might get moved to the archive folder because of MRM policy.
•Through this approach, you can only migrate 500000 emails.
•The maximum file size is 35 MB that you can migrate.
•You must create user accounts in Office 365 before initiating the migration.

How often does IMAP migration sync with Office 365?

IMAP mailbox syncs with Office 365 once every 24 hours after migrating IMAP to Office 365. This incremental synchronization process continues unless you stop or delete the migration batch.

How do I migrate from Outlook to an IMAP account?

For migrating Outlook to an IMAP email account, you need to configure your IMAP email account to MS Outlook. After that, you can simply migrate your mailbox data using the drag-and-drop feature.

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