Google Workspace to Microsoft 365 Migration Checklist

Use this checklist alongside our full Google Workspace to Microsoft 365 migration guide to make sure nothing gets missed before, during, or after cutover.

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Before you start (2-3 weeks out)

List every mailbox: user accounts, shared mailboxes (info@, accounts@, support@), and Google Groups used as distribution lists
Note total mailbox sizes to spot any that will take longer to migrate
Ask staff to archive or delete old email and Drive files they don't need
Identify business-critical spreadsheets that use Google-only formulas (QUERY, IMPORTRANGE, ARRAYFORMULA)
List all third-party apps connected via "Sign in with Google" or Gmail SMTP credentials
Confirm which Microsoft 365 plan you need - see Business Standard vs Business Premium
Purchase Microsoft 365 licences for all users
Confirm who manages your domain's DNS records and how quickly they can make changes

Setup phase (1-2 weeks out)

Add the TXT record to DNS to verify domain ownership in Microsoft 365
Create Microsoft 365 user accounts for every staff member
Pre-enrol every user in MFA (Microsoft Authenticator app) before cutover day
Install Outlook and the Microsoft 365 apps on staff devices ahead of time
Set up shared mailboxes and distribution lists in Microsoft 365
Start the pre-migration data copy for email, Drive files, calendars, and contacts
Test-convert a few critical spreadsheets to confirm formulas behave correctly in Excel

Cutover day

Run a final incremental sync to capture anything sent since the pre-migration copy started
Update DNS MX records to route new mail to Microsoft 365
Confirm new emails are arriving correctly in Microsoft 365
Reconfigure Outlook and mobile mail apps on every device
Regenerate recurring meeting links in Teams to replace expired Google Meet links
Keep the Google Workspace environment active as a safety net for 24-48 hours

After cutover

Reconnect third-party integrations (accounting, booking, CRM) to Microsoft 365
Confirm shared mailboxes are accessible to everyone who needs them
Check that centralised email signatures are applying correctly
Run a short Outlook orientation session for staff coming from Gmail
Rebuild any spreadsheets that used Google-only functions
Monitor helpdesk tickets closely for the first week and address device or access issues quickly
Once confirmed stable, decommission the Google Workspace subscription

Frequently Asked Questions

Will Google-only spreadsheet formulas break when we move to Excel?

Some will, functions like QUERY, IMPORTRANGE, and ARRAYFORMULA are Google-specific and don't have a direct Excel equivalent. The safest approach is identifying business-critical spreadsheets that use these functions ahead of time and test-converting a few of them before cutover, rather than discovering the problem after the fact.

What happens to our Google Groups used as distribution lists?

They need to be recreated as distribution lists or Microsoft 365 Groups on the new platform, they don't carry across automatically. This is exactly the kind of thing worth listing out during the "before you start" phase, since it's easy to overlook a group that's used for reporting rather than everyday email.

How long should we keep the Google Workspace subscription active after cutover?

Keeping it running for at least 24-48 hours after cutover as a safety net is standard practice, since some emails can still route to the old system during DNS propagation. Beyond that, it's worth monitoring for a week or so and confirming everything, including shared mailboxes and third-party integrations, is stable before decommissioning it.

Do staff coming from Gmail need training on Outlook?

A short orientation session helps a lot. Outlook works differently enough from Gmail, particularly around folders, rules, and shared mailbox access, that staff who've only ever used Gmail can feel lost for the first few days without a quick walkthrough.

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For related reading, see our Google Workspace to Microsoft 365 migration guide and migration cost breakdown.