| How to migrate emails to Office 365? |
This blog post explains how to migrate emails to Office 365 (Microsoft 365). First of all, this article applies to all types of sources. You can use this tutorial to migrate your mailboxes from any provider. It can be Exchange OnPremises, Lotus Notes, your IMAP or Zimbra servers, or even other Cloud providers such as Gmail or another Office 365 tenant. Hosted exchanges are also supported.
The migration process remains the same regardless of your source. First, you will need to create a project. Once done, you will create source and target connectors to connect to the different systems. The next step is to define your list of users to migrate and finally launch your migration.
To illustrate this migration process, we offer you this video that shows how to migrate your emails between two Office 365 tenants. Following this video, you will have links to the admin guides that cover other scenarios.
How to migrate emails to Office 365
Here are the admin guides that are relevant for your migrations. These guide show you how to migrate emails to Office 365 from various sources:
How to migrate emails to Office 365
Alternatively, Microsoft proposes free services to migrate emails to Office 365.
The following documentation shows how to migrate emails to Office 365 from :
- From Exchange OnPremises
- Using PST files
- using the IMAP service ( this migration will migrate mails but not contacts or calendars)
https://learn.microsoft.com/en-us/exchange/mailbox-migration/mailbox-migration
Note that these solutions are free. However they have several limitations. In particular they will not migrate permissions, distribution lists, Rooms and equipments etc…
Challenges to migrate emails to Office 365
Depending on the size of your project and the nature of the source, the challenges will be different.
Big Bang or cutover?
First, you have to determine you strategy of migration, will you do a big bang, staging, cutover migration?
The entirely depends on your organization. Are you able to cutover the entire company over a single weekend? If not, are you ready to envisage a coexistence between your two systems during the period of migration? This involves putting in place a dual email delivery system where mails have to reach the source or the target depending of if the user is migrated or not.
Domain Name Migration.
If you you are doing an office 365 to Office 365 migration, you will have to envisage migrating the domain.
See this article for more information : Mail Routing Solution
Throttling and Bandwidth limitations.
If your source is On-Premises, you have to determine if your server is able to support the load (ie a service pulling and extracting all the mailboxes in a limited amount of time).
Will your firewall support the load (Huge outgoing traffic for pushing all your mailboxes to the Cloud)?
Do you need to preserve bandwidth and migrate off hours to avoid to impact the users and your business?
