A Microsoft 365 to Google Workspace migration is not just a mailbox copy. It changes identities, sign-in, calendars, shared files, collaboration habits, mobile devices, DNS, support procedures, and sometimes the applications that send mail for the business. A successful cutover starts by deciding what must move, who owns each decision, and how the team will work if a step takes longer than planned.
Google's migration products and supported paths change over time. In its current guidance, Google says its older Google Workspace Migrate path for Exchange Online will no longer be available beginning in October 2026 and directs administrators toward its newer import tooling. Check Google's current go-live guidance and the documentation for your source, destination edition, and data type before choosing a tool.
1. Define the migration scope
Build an inventory before creating target accounts. Count active users, aliases, shared mailboxes, distribution lists, rooms, calendars, contacts, Teams or SharePoint content, OneDrive files, archives, delegated access, mobile devices, and applications that send through Microsoft 365.
Then classify each item: migrate, recreate, archive, replace, or retire. Email, calendars, contacts, shared drives, chat, and application data do not necessarily use the same migration method or preserve the same behavior.
Record for every user and shared resource:
- Current primary address and aliases.
- Target account, group, or shared-drive owner.
- Mailbox and file-data size.
- Delegates and calendar permissions.
- Retention, legal hold, or compliance requirements.
- Applications and devices that use the account.
- Whether the user belongs in a pilot or later cutover group.
2. Confirm identity, licensing, and administrator access
Verify that the destination Google Workspace edition supports the required services and migration path. Establish target administrator access, user naming, organizational units, groups, recovery information, and multifactor-authentication policy. Map each source identity to exactly one intended destination and resolve renamed users or duplicate addresses before data moves.
Google's migration planning guidance recommends defining phases, essential data, user groups, and the transition timeline before execution. Review its migration phase planning guidance while remembering that the available tool for Exchange Online is changing.
3. Audit DNS and every system that sends email
Mail flow changes when the domain's MX records point to Google, but MX is not the whole DNS plan. Inventory SPF, DKIM, DMARC, autodiscover-related records, verification records, subdomains, and third-party senders such as website forms, invoicing platforms, scanners, support systems, newsletters, and CRM tools.
Do not publish copied DNS values without validating them for the actual tenant and vendor. Microsoft maintains current Microsoft 365 DNS guidance; Google provides destination-specific records during Workspace setup. Preserve a before-state export and note current time-to-live values so changes and rollback are deliberate.
4. Choose a supported data-migration method
The right method depends on data types, source configuration, scale, licensing, deadlines, and supported authentication. Some methods move email but not files or collaboration spaces. Some preserve selected calendar or contact information but not every setting. Create a written matrix of supported, unsupported, transformed, and manually recreated items.
Avoid promising that every folder, permission, rule, meeting, label, archive, and application setting will arrive unchanged. Run a representative pilot and compare the result with the agreed acceptance criteria.
5. Protect the source and create a rollback plan
Migration is a copy and cutover project, not a reason to destroy the source immediately. Preserve required Microsoft 365 data and access through the validation period. Back up DNS, account mappings, settings, migration reports, website mail configuration, and any connector changed for the cutover.
Define the point at which mail routing can be restored, who can make that decision, and which changes are reversible. If the migration tool reports failed items, export the report, resolve the cause, and rerun the supported incremental or delta process instead of assuming the missing data will appear later.
6. Run a pilot with real business scenarios
Choose users who represent different mailbox sizes, delegates, calendar patterns, devices, and shared resources. Test:
- Inbound and outbound internal and external email.
- Aliases, groups, shared addresses, and delegated access.
- Calendar invitations, recurring events, rooms, and time zones.
- Contacts, search, labels, and expected historical messages.
- Mobile and desktop sign-in.
- Website forms, CRM notifications, scanners, and other senders.
- File sharing and ownership for the content included in scope.
7. Prepare the cutover
Schedule a change window, freeze avoidable account changes, run the final supported data pass, confirm help contacts, and communicate exact sign-in instructions. Tell users what will look different and which items are still processing. A short role-based guide is more useful than a long generic manual.
At cutover, update only the approved DNS and application settings. Record timestamps. Monitor mail queues, bounce messages, authentication, and the migration console. Keep a manual route for critical customer inquiries until the new flow is verified.
8. Validate after go-live
Check message counts and representative records rather than relying only on a green summary. Confirm executive and shared calendars, delegated mailboxes, distribution behavior, external sharing, mobile access, recovery methods, and important searches. Re-test every business system that sends email.
Document unresolved exceptions and ownership. Only decommission source licenses or data after the retention window, acceptance criteria, and business obligations are satisfied. For a wider look at connected-system risk, see website failures that can interrupt customer contact and the systems behind a business website.
Migration questions
Can a migration happen with no interruption?
Careful preparation can reduce disruption, but it is safer to define a cutover window and fallback than to promise zero interruption. DNS caching, authentication, data volume, user devices, and third-party senders can affect timing.
Should Microsoft 365 be cancelled immediately after cutover?
No. Keep the agreed source access and retention period until data, permissions, mail flow, and business obligations have been validated.
Does changing MX records migrate old email?
No. MX records direct new inbound mail. Historical messages and other data require a separate supported migration process.
Plan the move around business continuity
Almond Tech Services can help inventory accounts and senders, prepare DNS and cutover steps, coordinate supported migration tooling, and validate the live result. Explore email and workspace migration services or share your user count, source environment, and target date.
