Learn How to Migrate Zimbra to Office 365 Step By Step

In 2025, Zimbra offers limited and outdated features, and its inability to integrate with modern collaboration tools makes Office 365 a superior choice for users and organizations. Due to this, several mid- and large-sized organizations are moving from Zimbra to Office 365 to leverage advanced collaboration, better security, and cloud capabilities.

In this article, I have outlined a few ways in which users can easily perform Zimbra to Office 365 migration with the entire mail and document data. Go through this guide to learn about the pre- and post-migration checklists, the step-by-step migration guide, and troubleshooting. 

What are the Different Ways to Migrate Zimbra to Office 365?

There are two ways that you can use to perform this task – 

1. Using IMAP Migration (Manual Method)
2. Using Secure & Reliable Software (Automated Method)

But before getting into the steps, you need to perform a few pre-migration steps that ensure a safe, secure, and error-free migration from Zimbra to Office 365.

Preparation Phase

In the preparation phase, you need to prepare the source, i.e., Zimbra. Ensure below points:

1. Determine the Migration Scope

• Check and verify the types of data that need to be migrated from Zimbra, which can include emails, contacts, calendar, and documents.
• Check the types of mailboxes that needs to be moved, and its size. In- case of shared mailboxes, ensure respective permissions associated to these mailboxes.

By performing these steps, you can determine the scope and approximate time it will take to complete the process.  

2. Backup Current Zimbra Environment

Since it’s you organizational data, it needs to be secured, and backed up to multiple locations, just to ensure proper compliance and regulations.

• Use the native feature of Zimbra, i.e., (zmbackup), to create a full backup of the current environment. 
• Make sure to store these backups in multiple locations to make it redundant, secure, and accessible in any situation.

3. Set up Destination 

In the destination, you need to do a few crucial things to ensure safe email routing and email migration from Zimbra to Office 365.

• Verify domain ownership at the Microsoft 365 Admin Center. For this, you have to add a TXT record in DNS settings. 

Note: You do not need to remove the domain from source i.e. Zimbra. You only need to add TXT to verify the ownership of domain. It will co-exist in the both places i.e. Zimbra and Office 365.

•  Create users, groups and shared mailboxes as it is present in the source Zimbra environment. It will maintain consistency and remove the chances of potential errors.

Possible Approaches for Zimbra to Office 365 Migration

Let’s start with the manual method first via IMAP.

1. Using IMAP Migration (Manual Method) for Zimbra to Office 365 Migration

Enable IMAP in Zimbra

Note: Before moving to the steps, make sure to enable IMAP in Zimbra. Follow these steps below:

• Using admin credentials, log in to Zimbra Admin Console. 
• Navigate to Global Settings > IMAP.
• Enable IMAP with SSL/TLS.

Configure Office 365 Migration Endpoint

Step 1. In Exchange Admin Center, navigate to Recipients > Migration > IMAP Migration.

Step 2. Enter Zimbra IMAP server details:

• Server – mail.yourdomain.com
• Port – 993
• SSL – Encryption

Create and Upload CSV File. 

• Step 1. Generate a CSV with Zimbra email addresses and passwords.
• Step 2. Upload via Add Migration Batch to initiate sync.

There are the brief steps, there are n number of steps that you need to perform in order to migrate Zimbra email to Office 365.

For detailed information, check the official Microsoft 365 documentation.

Why You Should Avoid the Manual Method for Bulk Zimbra to Office 365 Migration?

There are various shortcomings associated with the manual method, such as:

• Supports Only Email Workload – With the IMAP migration, you can only migrate email data of a user’s account from Zimbra to Microsoft 365. It does not migrate contacts, calendars, or documents.
• Does not Offer Selective Data Transfer – It does not offer any option to apply date filter to migrate only the required data. 
• Technical & Time Consuming – If you check the Microsoft official documentation linked above, you will be overwhelmed with the multiple stages of steps. The manual method is core technical and lengthy. It requires an utmost technically sound person to execute the entire Zimbra to Microsoft 365 migration error-free.
• Absence of Migration Report or Log – The manual processing is unable to generate a detailed or summary report of migration. Due to this, organizations or admins often face issues such as – lack of transparency, troubleshooting challenges, etc.

Now the obvious question comes to our mind – how to overcome these limitations. 

Best Alternative to Ensure Smooth Migration from Zimbra to Office 365

To overcome all these limitations of manual methods, organizations often choose a reliable and automated software to automate the entire task to ensure business continuity. One such software is the SysTools Zimbra to Office 365 Migration Tool. 

Download Now Purchase Now

I have tested this software with a workload of 250 Zimbra user accounts. The software not only offered modern features such as date filter, priority-based migration, incremental migration, etc, but also ensured data consistency throughout the entire migration to Microsoft 365. 

Check out the Steps Below to Migrate the Entire Zimbra Data to Office 365

Step 1. After downloading the software, launch it on your system. Choose Zimbra as the source and Microsoft 365 as the destination migration platform.

Step 2. Enable the required mailbox workload that you want to migrate. The software supports all mailbox categories, including email, contacts, calendars, and documents. Apply date filter if required. 

Step 3. Enter source Zimbra Admin Credentials and click on the validate button. 

Step 4. Enter destination Microsoft 365 admin credentials and click on the validate button. 

Step 5. For bulk user migration, you can add users using a CSV file. For limited users, you can proceed with the fetch user option.

Step 6. Select the required user accounts and mark the star icon for priority migration. Click on the validate button once the validation is completed. Hit the start migration button.

With these few steps, you can easily migrate Zimbra email to Office 365 along with other mailbox data. 

Give It a Try – Use the Free Demo

Before purchasing the full version of this software, organizations and IT administrators can download the free demo version. The demo version allows you to migrate emails from 2 user accounts to Office 365. By using the free demo, you can experience the real-life software performance, features, and ease of use. 

Also Read: How to Migrate Zoho Mail to Office 365?

Wrapping Up

Moving from Zimbra to Office 365 is a timely necessity, especially for those organizations that want to leverage modern cloud capabilities, such as robust security, modern collaboration, and cloud integrations. 

Hence, in this step-by-step guide, I have outlined two ways for performing Zimbra to Office 365 migration. While the manual method has its limitations, you can easily overcome them by switching to the mentioned software above.