Office 365 Tenant-to-Tenant Cutover Email Migration: 7-Day Planning, Design and Migration

IT Partner LLC

Seamlessly transfer email data and mailboxes between Office 365 tenants during mergers or separations. Ensure continuity for users, minimize disruptions, and enables a smooth transition.

Occasionally, a customer needs a migration inside the Microsoft 365 cloud platform. For example, if one company acquires another company and both are using Microsoft 365, there may be many reasons to start merging.

Our objective is to provide planning, design, and migration of email service from one Microsoft 365 tenant to another. While the domain is transferring from the source tenant to the new tenant, incoming mail will not be received for about 24 hours. This is due to domain name binding features in Exchange Online.

To avoid the loss of emails during the transfer period, you can consider the extended migration service.


  1. Export resources (mailbox-enabled users, contacts, groups, etc.) from the source tenant
  2. Import resources to the destination tenant via AD Connect or CSV import
  3. Do pre-stage migration (only emails and email folders older than 30 days)
  4. Final mailbox migration with calendars, contacts, rules, and other data
  5. Change records in domain zones to accommodate migration needs


  1. Provide a dedicated point of contact responsible for working with IT Partner
  2. Coordinate any outside vendor resources and schedules
  3. Configure all network equipment, such as load balancers, routers, firewalls, and switches
  4. If Microsoft Outlook or other desktop email clients are used to connect to Microsoft 365, deploy email software on client workstations
  5. Perform changes to internal and external DNS, as required
  6. Assist with identification of high-risk users (top executives and VIP users, users with 50 GB mailboxes or larger and/or 30 GB deleted folders or larger)
  7. Recreate new Outlook profile on all client workstations, if desktop Outlook version is used
  8. Inform users about upcoming changes and provide the necessary information

NOT INCLUDED IN THE PROJECT COST (Additional services available at an extra charge):

  1. Informing users about upcoming changes
  2. Customer team training (could be added as an additional service)
  3. Migration of corporate documents to SharePoint Online (could be added as an additional service)
  4. Desktop software settings

Upon completion of the project, we will provide a project closeout report. This document will indicate the final project status, including acceptance criteria matching, outstanding issues, and the final budget. If you require more extensive documentation, it can be provided for an additional fee.


  1. You must have global admin level access to the source Microsoft 365 tenant
  2. You must have global admin level access to the destination Microsoft 365 tenant, with Exchange Online licenses available
  3. You must have access to your email domain DNS zone

PLAN (may vary depending on your needs):

  1. Kickoff meeting
  2. Pre-migration source system health check
  3. Creating users or configuring AD Connect tool
  4. Email migration start
  5. Verification of email migration
  6. Changing MX record to new Microsoft 365 tenant
  7. Final email migration
  8. Post-migration tasks


  1. Users can access Exchange Online on their desktop PCs, mobile phones, and tablets from any place, any time
  2. Old Microsoft 365 tenant successfully migrated to new Microsoft 365 tenant and accessible by all users
  3. All necessary Transport rules are created and working
  4. Mail can be sent and received using Exchange Online
  5. Exchange Online Protection is configured and working


Project Management Fee $900.00 + $35.00 per mailbox

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