1. Introduction : Zimbra to Microsoft 365 Migration

Zimbra to Microsoft 365 Migration
Cloudiway loginStores details and provides communication between the systems you already use.https://portal.cloudiway.com/
Help CenterOur extensive knowledge base is always accessible, with videos, troubleshooting tools, samples and more.https://help.cloudiway.com/
Microsoft 365 account with impersonation privilegesUsed for impersonation to access mailboxes (read or write). This doesn’t have to be the tenant’s admin account. However, it must be an administrator account if you wish to migrate the permissions. The account must be able to bypass SSO and authenticate using username/password credentials with the format: user@tenant.onmicrosoft.com (with a password set to never expire).We recommend you create a non-federated domain account (on your *.onmicrosoft.com domain) especially for
migration. After all migrations are complete, simply delete this account. We provide steps below to help you set up an account with impersonation privileges if you don’t already have one.

6. Zimbra to Microsoft 365 Migration

6.1. Create your source and target connectors

For Cloudiway to migrate your email, it needs to be able to communicate with both your source and target domains. To do this, Zimbra to Microsoft 365 Migration requires connectors that will store the credentials used to connect to the endpoints. You will need to set up a connector for each source tenant you wish to migrate and each target tenant that mail should be migrated to.

Follow the steps on the pages below to configure Zimbra and Office 365 connectors:

Create Connectors guide

Create A zimbra Connector

 Create a Microsoft 365 Connector

Mail Migration Global Settings
Mails migration User Listing
2. Click on MANAGE and select Import
Mails migration UserList Import

3. If required, click on Download sample CSV and add your users to the CSV file using the sample headers (FirstName; LastName; SourceEmail; TargetEmail; BatchName)

4. When you have a complete CSV file with the correct headers, click on the BROWSE button

5. Locate your CSV file within your own file system, and double-click on it to select it

6. Select the appropriate connectors in the Source and Target fields

7. Click on the UPLOAD button.

Zimbra to Microsoft 365 migration

6.3.2. Option 2: Import Users tool

Cloudiway’s Import Users tool helps you to retrieve users from your source tenant. The functionality works via Identity Access Management. The tool requires you to specify any transformation rules you wish to apply. It will then add new users in the Mail Migration User List view within the Cloudiway platform.

This is an advanced tool that is best used in partnership with Cloudiway consultants. If you are interested in using this option, please get in touch with your Cloudiway contact.
6.3.3. Option 3: Create a single user

Many of our first-time customers create a single user for testing purposes. This provides a means of watching the migration process without affecting all users. Single users can also be created for migrations affecting just a few users.

Click on MANAGE > Create User and enter the following details:

Mails migration Create Users

What a migration pass takes to complete depends on a lot of factors. Find out more about the migration performance:

If you have moved the source domain and need to perform one more delta pass, the Switch Domain global action will need to be used:

You can create user batches from the Batches tab to easily group subset of mailboxes. Click on the + icon and enter a batch name:


After creating the different batch, under Users tab, select the users you want to assign to a specific batch, click on BATCH button and Add to Batch:

Add to batch

To start your Zimbra to Microsoft 365 Migration, select the users or batch you wish to migrate.

  • For users, under Users tab, select all the users you want to submit and click on MIGRATION, then the Start button.
User list
  • For user batch, under Batches tab, select the user batch you want to submit and click on MIGRATION, then the Start button.
Add users to batch

Your migrations will be scheduled and will begin as soon as cloud resources are available.

7. Other migration options

7.1. Mailbox permissions migration

You can migrate mailbox permissions for mailboxes through the Cloudiway platform.

Migration of permission isn’t performed during the migration of the mailboxes but through a dedicated job.

The migration of the permissions will migrate permissions on the mailboxes, on the primary and secondary calendars.

WarningIf permissions were applied to mail-enabled security group, the mail enable security group must exist at the destination for the permission to be applied correctly.

Click on User List, select the users, go to MIGRATION, then click on Migrate Permissions

Migration Permission

NOTE: Once you start the process of permissions migration, it cannot be stopped.

7.2. Migration to archive mailboxes

The Zimbra mailboxes can be migrated to the Office 365 online mailboxes, to the Office 365 archives, or to a mix of both.

During the Zimbra to Microsoft 365 Migration, a single mailbox can be split into the online mailbox and archive.

Note: to migrate content to archives, In-Place archiving must be enabled for the user, learn more: https://technet.microsoft.com/enus/library/jj984357(v=exchg.150).aspx.

In the Cloudiway platform, you can migrate either only old emails or all the emails to the target archive mailbox. So 2 options:

  • From the Global Settings section, Archive Mails Older Than is to migrate the emails older than specified date and time in the past to the target archive mailbox. Keep Migrate Everything to Archives disabled.
Archive Mails

In this example emails older than April 7 2020 will be migrated to the archive mailbox:


Click on the Save button, when your migration starts, any emails older than the date you specified will be migrated to an In-Place archive. More recent items will be migrated to the target mailbox.

  • From the Global Settings section, Migrate Everything to Archives is to migrate all the emails to the target archive mailbox. In the Mail Global Settings, enable Migrate Everything to Archives and all emails will be migrated to the target archive mailbox:
Archive mails

Click on the Save button, when your migration starts, all emails will be migrated to an In-Place archive.