Set up a cutover migration from on-premises Exchange Server to Office 365

Applies to: Office 365

As part of the process of deploying, you can choose to migrate the contents of user mailboxes from Exchange Server to Office 365 mailboxes. We recommend a cutover migration when:

• Your current on-premises email organization is Microsoft Exchange 2003, Microsoft Exchange Server 2007 or Exchange Server 2010.

• Your on-premises Exchange organization has fewer than 1,000 mailboxes.

Setting up email is one of the required steps in setup path for Office 365. For more information, see Streamline your deployment of Office 365.

Things to consider

Setting up a cutover migration to Office 365 requires careful planning. Before you begin the cutover migration to Office 365, there are few things for you to consider:

• You can move your entire email organization to Office 365 over a few days and manage user accounts in Office 365.

• You can migrate a maximum of 1,000 Exchange 2003, Exchange 2007, or Exchange 2010 mailboxes to Office 365 by using a cutover Exchange migration.

  Note

  A cutover migration from on-premises Exchange to Office 365 is used by organizations that have less than 2,000 mailboxes, although the recommendation is for organizations with less than 1,000 mailboxes.

• After the new Office 365 mailboxes are created, email messages, contacts, and calendar items from each on-premises Exchange mailbox are copied to the corresponding mailbox in Office 365.

• After the initial migration, the on-premises Exchange and Office 365 mailboxes are synchronized every 24 hours so that new email sent to the on-premises Exchange mailbox is copied to the corresponding Office 365 mailbox.

Impact to users

After you configure your on-premises and Office 365 organizations for a cutover migration, the following post-configuration tasks might impact your users:

• You must make sure that your users’ desktop computers are updated and set up for use with Office 365. This allows them to use their local user credentials to sign in to Office 365 from desktop applications. Users can update and set up their desktops themselves, if they have permission to install applications, or you can install the updates for them. After making the updates, users can send email from Outlook 2013, Outlook 2010, or Outlook 2007.

• E-mail sent to on-premises users whose mailboxes have been migrated to Office 365 will be routed to their on-premises Exchange mailboxes until the MX record is changed.

Ready to start?

To configure a cutover migration to Office 365, you need to be comfortable doing these tasks:

• You install and configure Exchange Server.

• You configure Exchange Server by using the Exchange Admin Center.

• You change your organization's MX record to point to Office 365 when the migration is complete. Your MX record is how other mail systems find the location of your email system. Changing your MX record allows other mail systems to begin to send email directly to the new mailboxes in Office 365. We provide instructions on how to do this for many DNS providers. To configure your public Domain Name System (DNS) servers you need to change your organization's MX record to point to Office 365 if you choose to route all incoming Internet mail for your on-premises Exchange organization through Office 365.

If you’re comfortable with what’s involved in migration, you’re ready to get started.

Get started

See Tasks for performing a cutover migration to Office 365 to get started.

Here is an option for setting up your cutover migration to Office 365.

Method	Description	More information
	Hire a partner to help with your cutover migration	If you’re having trouble setting up a cutover migration to Office 365, you can find a list of partners in the Office 365 Marketplace that can help you.