Zimbra to Office 365 Migration

User Query

We receive inquiries from users looking to transition from Zimbra to Microsoft 365. There are multiple reasons for migration, ranging from inflexible Zimbra filters to changing business requirements or opting for a more secure solution with all advanced features. Keeping all of these requirements in mind, we decided to document the methods for performing and ensuring a smooth migration. Here's a query from a user who approached us in search of a solution.

“Hello EdbMails team. Previously, we used Zimbra for email communication. However, as our organization has grown across the globe, we intend to migrate to Microsoft Office 365. We have no idea how to migrate large amounts of data. Can you recommend a solution or a step-by-step procedure to make our move go as smoothly as possible?”

Zimbra to Office 365 migration plan

Planning is one of the most important factors before you migrate to Office 365. You must prepare the source and target environments and have a backup plan in place to avoid potential risks and data loss. Here is a checklist of points to consider for the migration.

1. Take a complete backup of your existing mailboxes, mail items and data on the source.
2. Determine the size of the data and number of mailboxes you want to migrate from Zimbra to Office 365.
3. Make a list of all the data and permissions from Zimbra that you want to transfer.
4. Create appropriate user mailboxes on Office 365 and assign licenses to them.
5. Ensure you have enough network capacity and bandwidth to migrate.
6. Communicate the migration plan to your end users and inform the stakeholders.
7. Perform a test or pilot migration before you start the actual one

I. Pre migration activities for Zimbra to Office 365 migration

The following pre-migration activities are common for both the migration methods described in this article.

1. Make sure you have admin access on the source and target server
   

   The admin account that has all the necessary permissions to migrate mailboxes on behalf of all the users in your organization. Assign the global administrator rights to the user in Zimbra. Also assign the Organization Management role group and impersonation rights to the admin user on Office 365.

2. Export all the users from Zimbra as a CSV file
   • a. Open the Zimbra Admin Panel
   • b. On the search toolbar, expand and click ‘Accounts’
   • c. Type the domain name of the accounts to be exported
   • d. Expand the Settings toolbar on the upper right and click ‘Download’
3. Create Office 365 mailboxes and assign licenses to them
   •  Add users and assign licenses to Office 365 users
   •   Assign Microsoft 365 licenses to user accounts
4. If you plan to migrate your mailboxes to Office 365 Public folders, ensure that you create and configure the Public folder mailboxes on the target server.

     Create Office 365 Public folder and assign mailbox user

5. Similarly, if you want to migrate mailboxes to Office 365 In-Place archive, enable them from the admin center.

    Steps to enable archive mailbox in Microsoft 365.

6. If you have a custom email domain from the source which you want to retain and receive emails to, you must add and verify the domain on Office 365.

    Steps to add a custom domain to Office 365 and steps to add DNS records to connect your domain.

7. Configure Office 365 to send and receive large messages.

    Follow the steps to increase the message size on Office 365 to 150MB. See message size limits on Office 365 for more information.

How to migrate Zimbra to Office 365?

You can perform the migration with the following two methods.

1. Migrate Zimbra to Office 365 with the archive method
2. Migrate mailboxes directly to Office 365 with EdbMails IMAP migration

1. Steps to migrate Zimbra to Office 365 with the archive method

In this method, you must export the TGZ file from the Zimbra client and convert the TGZ file to PST. Then, import the PST file into Microsoft 365 with Azure AzCopy.

• Step 1: Make sure you have admin access on the source and target server
• Step 2: Export the archive TGZ file from Zimbra desktop

  The TGZ file contains all the mail data from your Zimbra webmail account. The following steps describe how to export the TGZ file.

  • Launch Zimbra desktop application
  • Click the ‘Preferences’ gear tab on the menu bar
  • On the left menu, click ‘Import/Export’
  • Select ‘Advanced Settings’ and select the Data Types you want to export
  • Click ‘Export’ and save the TGZ file on your computer

  After the export operation, you must convert the TGZ file to PST

• Step 3: Migrate the converted PST file to Office 365 using AzCopy

  In this step, you use Microsoft’s network upload option to import the PST file into Office 365.

  • a. Copy the network upload Shared Access Signature (SAS) URL from Microsoft compliance center
  • b. Download and launch the Azure AzCopy tool on your computer
  • c. Upload the PST to Office 365 from the Azure AzCopy
  • d. Create a mapping file for the import operation
  • e. Create a PST import job and start importing the PST to Office 365

  When using this method, there are a few things to keep in mind. To convert the TGZ file to Outlook PST, you must use a suitable application. Uploading the PST files with AzCopy and importing your mailboxes may be technical and difficult to complete without proper assistance and support.

  In addition to this method, you can migrate your emails via IMAP by creating a list of users to be migrated in a .CSV file and creating a migration endpoint from the Exchange admin center (EAC). However, if you are looking to migrate large data, then both of the aforementioned approaches can be very complex and time-consuming to follow. As a result, we suggest a simple Zimbra migration method with EdbMails application

2. Steps to migrate Zimbra to Office 365 with EdbMails

In this section, we will go over EdbMails IMAP migration for migrating your data from Zimbra to Office 365. The benefit of using this application is that you don't have to worry about the technical aspects of the migration process. You can connect to your source server, load the mailboxes in real time, and select the ones that need to be migrated from a graphical user interface.

• Step 1: Download EdbMails software setup for IMAP migration
  • Download EdbMails and install the application on any computer that is connected to the source and target environment. You can also perform the migration operation by installing EdbMails on a non-Exchange computer.

    

      See a detailed list of EdbMails system requirements for IMAP migration.

  • Launch the application and click ‘Login’ or ‘Start Your Free Trial’

    

  • Select the migration method as IMAP migration.

    

• Step 2: Connect to a single user or multiple users mailbox on Zimbra

  Obtain the Host Name on Zimbra (imap.zimbra.com or zimbra.xmission.com) and enter it as shown. You can also get your IMAP server name from Outlook on the web.

  Select the option SSL / TLS, enter the Port Number as 993 (For secure IMAP connection) and enter your user credentials.

  

  If you want to migrate multiple mailboxes, select ‘Multiple (bulk) Users/Accounts Migration’. Download the sample CSV file and add in the required details such as mailbox name, password, host name and port. Load the CSV file into EdbMails and verify the list mailboxes to continue.

    See steps to connect to single and multiple users in EdbMails IMAP migration

  

• Step 3: Select mailboxes from Zimbra and connect to Office 365
  • Select the mailboxes and folders from the left panel.
  • Click ‘Migrate to Office 365’ to set up the connection with the target server.

   See tips to optimize IMAP migration to Exchange online

  

  Tip: If this is the first time you’re migrating with EdbMails, the migration is a full migration. On subsequent migrations from the same source to the target, the migration is incremental.

  EdbMails provides the following additional options to help you customize the migration task.

  1. Additional Include and Exclude Filter Options
  2. Filter emails by Date: Migrate to Office 365 by applying the Date filter
  3. Filter emails by Size: Exclude emails from migration larger than a specified size.
• Step 4: Connect to target Office 365 as Global Admin User

  EdbMails supports both modern and classic authentication. Connect to the target server by selecting Auto or Manual registration for modern authentication and the connection method as Mailboxes, Public folder or Archive Mailbox. You can also connect to the mailboxes by loading a CSV file of users from the Office 365 tenant.

    Connect to Office 365 server using secure modern authentication

• Step 5: Map the mailboxes / folders between the source and target

  The mapping activity in EdbMails can automatically match and map the mailboxes and folders between Zimbra and Office 365. This activity saves time when you’re migrating a large number of mailboxes.

• Step 6: Start the migration to Office 365 from Zimbra

  Start and monitor the migration operation after you complete the mailbox mapping. Finally, verify the count of migrated emails, folders and mailbox items with EdbMails text-based log report. You can also pause and resume the migration.

    If you have exported a PST file of the mailboxes from Zimbra, EdbMails can help you migrate PST data to Office 365, which is a much faster and easier method than Microsoft's network upload method.

Post-migration tasks

Step 1: Update the MX records to point to Office 365

If you have not done this step previously, change the DNS records known as MX records to enable and receive email messages on the target Office 365 server. In addition to this setup, configure the Autodiscover record to allow Outlook to connect to the migrated mailboxes.

Step 2: Create a new Outlook profile for users in the new domain

Configure and recreate the Outlook profile for each user in your domain if Outlook has problems connecting to Office 365 mailboxes.

Migration troubleshooting

See the migration troubleshooting guide for possible solutions related to common errors. For more information on EdbMails IMAP migration, see frequently asked questions (FAQs)

Benefits of using EdbMails to migrate Zimbra to Office 365

1. Direct migration to Microsoft 365 without the TGZ file

   EdbMails enables direct migration from source server to target without the need for intermediate steps such as exporting to TGZ or manual conversion procedures.

2. No-duplicate migration feature

   On subsequent migrations to the target, EdbMails avoids duplicates and migrates only new and updated items (incremental). This is extremely useful if you intend to remigrate from Zimbra to O365 in stages or at a later date. However, the initial migration with the application is always a full migration.

3. Migrate to Office 365 Public folders EdbMails enables you to migrate all the source folders and emails to Office 365 Public Folders and Shared Mailboxes. You can directly transfer the data to the required mailbox without requiring PowerShell scripts.

   See how to create Public folders in Office 365

4. Granular migration with advanced filter settings

   There are some situations where users would prefer not to migrate everything. EdbMails granular migration makes this possible by enabling you to migrate your data at the item level. There are also include and exclude filter options to help you select items based on various conditions.

5. Export Zimbra emails to Outlook PST format

   If you want to backup all of your Zimbra emails, EdbMails can help you export IMAP to portable Outlook PST format. Simply select 'Export to Outlook PST' from the main interface and specify a location for saving the file.

     Click here if you would like to know more about all of EdbMails IMAP migration features