MICROSOFT 365 TO MICROSOFT 365 MAIL MIGRATION GUIDE

1. Microsoft 365 Mail migration with Cloudiway

2. Security

For more information about security, please refer to this article.

3. Performance

4. Microsoft 365 Mail migration scope

4.1. What can be migrated and what are the limitations?

You will find what can be migrated and the limitations between Microsoft Office 365 tenants on this page:

5. Pre-migration configuration

5.1. Before you start

Before you start, you need the following accounts.

NameDescriptionLocation
CloudiwayAccount to configure the Cloudiway Platform for your migration.https://portal.cloudiway.com
Office 365 AdminsUsed to configure Azure Active Directory Application and associated permissions both in source and target tenants.https://aad.portal.azure.com

5.4.6. Create your shared mailboxes

Cloudiway provides a tool to provision and migrates shared mailboxes in a separate menu. In the Mail Migration section of the tools, you will see a Shared Mailboxes option. This tool can be used to discover your shared mailboxes and provision them to the target tenant so you don’t have to do it manually.

More details on how to use this feature can be found here:

6. Use the Cloudiway platform to migrate your mailboxes

Most of the options are self-explanatory.

The Convert Email Address option needs further explanation. The Convert Email Address option is switched on by default (and is best left on). When activated, this option rewrites email addresses found in the email headers, calendar items and mailbox permissions and replaces source email addresses with their corresponding target email addresses in the mapping table. Therefore, it’s important that all users exist in the mapping table before migration begins.

Archive Mails Older Than is to migrate the emails older than specified date and time in the past to the target archive mailbox and Migrate Everything to Archives is to migrate all the emails to the target archive mailbox. See the 7.6.2. Migration to archives section for further information.

Click on the Save button at the bottom of the screen to update your global settings.

6.3. Import or create your users into Cloudiway platform

There are a number of ways to add users that you wish to migrate. These include:

  1. CSV file import.
  2. Cloudiway’s mailbox discover tool (Get List).
  3. Create a single user.

Regardless, each user will need to be assigned a license type — Trial (limited to 100 MB), Education, Standard, Archive, or No License (used for adding users to your mapping table regardless of migration plans).

Note that importing users into Cloudiway won’t create the user mailboxes in the target tenant. See 5.4.3 Create your user mailboxes

6.3.1. Option 1: CSV file import

If you have a CSV file of all your users, you can upload the file to Cloudiway. The file must have the following fields in the header row:

FirstName;LastName;SourceEmail;TargetEmail;SourceRecipientType;TargetRecipientType;BatchName

1. Ensure you’re still in the Mails Migration area of portal.cloudiway.com and go to User List, Shared Mailboxes, Room & Equipment or Distribution Lists sections and then click on Migration, select Get List:
user list
2. Click on MANAGE and select Import
Migration export import

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

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

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

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

6. Click on the UPLOAD button.
upload

If you see any error messages, check your CSV file to ensure it has seven columns, each with a separator (including the last) and try uploading again.

6.3.2. Option 2: Get List

Cloudiway’s Get List tool helps you to retrieve mailboxes from your source tenant. There are 5 Get List tools corresponding to the different sections:

  • User List: to discover only user mailboxes.
  • Shared Mailboxes: to discover only shared mailboxes.
  • Room Equipment: to discover only room and equipment mailboxes.
  • Distribution list: to discover only distribution lists.
  • Archive: to discover only archive mailboxes.

Under each of those sections, go to Migration, and select Get List.

Get list

The tool requires you to enter the Source and Target Pool of connectors.

Office365 Get Userlist

Then to specify:

  • The Matching Rule:
    • Mail Exact Match: the source email = the target email (bob.marley@sourcedomain.com > bob.marley@sourcedomain.com)
    • Keep Email Prefix Same as Source: only the domain name changed (bob.marley@sourcedomain.com > bob.marley@targetdomain.com)
    • FirstName.LastName (i.e. bob.marley@targetdomain.com)
    • F.LastName (i.e. b.marley@targetdomain.com)
    • FLastName (i.e. bmarley@targetdomain.com)
    • LastNameF (i.e. marleyb@targetdomain.com)
  • The Target Domain. Specify the target domain assigned to the target emails addresses in the list.

It will then add new users to the User List. You can monitor the progress of this task in the User List: Get List Logs.

user list

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.

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

Create new user

Short-Term Mail Routing For Google and Office 365 Cutover Mail Migration

If you have moved the source domain before performing one or more delta passes, the Switch Domain global action will need to be used:

You can submit as many migration passes as you want for 3 months and until consuming the amount of GBs allowed by the assigned licenses but usually, you only need one before the cutover and another after the cutover. Find out more about the delta migration passes:

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

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

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

Batch

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:

User list
Start user list
batch

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

NOTE: When migrating by user batches during a long period of time you may want to enable email forwarders.

For more information, please see this article:

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

user list

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

7.2. X500 addresses and LegacyExchangeDN migration

From the Transfer X500 section of Global Actions, you can migrate the X500 addresses and LegacyExchangeDN from your source mailboxes to your target mailboxes.

Select your Source and the Target, click on START.

Transfer X500

You will see a Scheduled status, and Completed when the process is finished.

7.3. Shared mailbox migration

From the Shared Mailboxes section under Mail, you can recreate and migrate Shared mailboxes from your source tenant to your target tenant.

For more information, please see this article:

7.4. Rooms and Equipment mailbox migration

From the Rooms & Equipment section under Mail, you can recreate and migrate Rooms and Equipment mailboxes from your source tenant to your target tenant.

For more information, please see this article:

7.5. Distribution List migration

From the Distribution Lists section under Mail, you can recreate and migrate distribution lists from your source tenant to your target tenant.

For more information, please see this article:

7.6. Archive mailbox migration

7.6.1. Migration from archives mailboxes

To migrate your archives, create your users from the Archive menu.

Archive mailboxes

Once complete, select your entries, go to MIGRATION then Start.

Note: by default, archives are migrated to archives. You can eventually decide to migrate an archive to a standard mailbox.

Archive Entry Standard
  • 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:

Archive mails

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.

8. Troubleshooting