Moving from Google Workspace to Microsoft 365: What Businesses Need to Plan

Moving from Gmail to Outlook may sound straightforward. But Google Workspace often contains far more than email.

A business may depend on Google Calendar, My Drive, Shared Drives, Docs, Sheets, Forms, Apps Script, Meet, Chat and "Sign in with Google" across third-party applications. A successful move to Microsoft 365 must therefore address the complete working environment — not merely the mailboxes.

The hardest part is rarely copying the data. It is understanding everything the business has built around it.

Why Businesses Move to Microsoft 365

Organisations move from Google Workspace for a range of practical reasons. Staff or customers may expect Outlook, Teams and the desktop Office applications. The business may want Microsoft 365 Business Premium for its combination of productivity, device management and security tooling — Microsoft Entra ID, Intune, Defender and Conditional Access, where licensing permits. Windows device management may be becoming difficult, Google and Microsoft subscriptions may overlap, or a merger with a Microsoft-based organisation may make consolidation sensible.

None of these reasons makes Google Workspace a bad platform. They simply mean that, for some businesses, Microsoft 365 fits better with how they now work.

What a Complete Migration Includes

Migration projects often begin with "we just need to move Gmail into Outlook". The real environment usually includes email, calendars, contacts, aliases, groups, meeting rooms, delegated mailboxes, My Drive, Shared Drives, Google-native files, public and external sharing, Google Forms, Apps Script, Google Sites, browser profiles, Google-authenticated SaaS applications, mobile devices, security policies, Google Vault, retention requirements, backup, DNS and email filtering.

A complete migration plans for all of it — deciding what moves, what is redesigned, what is archived and what is deliberately left behind.

Microsoft's Current Native Migration Tools

Microsoft now provides supported, first-party migration routes for the main Google Workspace workloads. Gmail, calendars and contacts can be migrated through Microsoft's supported Google Workspace migration process in Exchange Online. Microsoft Migration Manager can scan, assess and copy supported My Drive content into OneDrive, and supported Shared Drive content into appropriate SharePoint or Teams-connected SharePoint destinations.

These native tools reduce the need for third-party migration software in many standard projects. What they do not remove is the need for discovery, destination design, identity planning, security configuration, project management, validation and user support. The tool moves data; someone still has to design and manage the transition around it.

Gmail Labels Versus Outlook Folders

Gmail organises mail with labels, and a single message can carry several labels at once. Outlook uses folders, where a message lives in one place. Migration therefore has to translate one model into the other, which can produce unfamiliar folder structures or items that appear duplicated. Staff who lived in Gmail search and labels need to understand how Outlook folders, categories and search behave — otherwise the migration feels like a downgrade even when nothing has been lost.

Google Drive Versus OneDrive and SharePoint

Google Drive has two homes for files: My Drive (personal working files) and Shared Drives (team-owned content). Microsoft 365 splits this differently: OneDrive is best suited to files mainly owned and used by one person, while SharePoint — often surfaced through Teams — holds departmental, operational, project and shared company information.

This is a design decision, not a copy job. Moving every Shared Drive into one large SharePoint library simply relocates the disorder. Good destination design considers ownership, department, sensitivity, retention, external sharing and how people will actually find things afterwards.

Google-Native Files

Google Docs, Sheets and Slides are not files in the conventional sense — they are documents that live inside Google's editors. During migration they are typically converted into Word, Excel and PowerPoint formats. Most convert well, but complex formatting, formulas, embedded scripts, comments and behaviours can change. Business-critical spreadsheets and documents should be identified during discovery and checked after conversion, rather than discovered broken weeks later.

Permissions and External Sharing

Google sharing and Microsoft permissions use different structures, and years of accumulated sharing rarely map cleanly. Historic over-sharing should not be copied blindly into the new environment — migration is the natural moment to review who can see what. Existing public Google links may also stop working or need replacement, which matters if they are embedded in websites, proposals or customer communications.

Forms, Apps Script and Google Sign-In

Three dependencies deserve special attention because no migration tool moves them automatically:

• Google Forms and their connected workflows need separate assessment and usually rebuilding in Microsoft Forms or another tool.
• Apps Script automations do not become Power Automate workflows by themselves — each one needs to be understood and consciously recreated, replaced or retired.
• "Sign in with Google" may still control access to third-party business applications. If Google accounts are closed before those sign-ins are changed, staff can be locked out of systems that were never part of the "email migration".

Data may migrate while the process, permission or behaviour built around it does not.

Security Before Migration

Business data should not be moved into a Microsoft 365 tenant that has not been secured. Before migration, administrator ownership should be clear — named Global Administrators, cloud-only emergency access and MFA on every privileged account. Security Defaults or Conditional Access, external-sharing settings, audit logging and Microsoft Defender and Intune (where licensed) should be reviewed or configured first.

Moving platforms does not automatically improve security. The target must be configured properly. And the business — not only an external supplier — should hold appropriate administrator access to the tenant it is moving into.

Pilot Users and Coexistence

A representative pilot migrates a small group of real users and real data first: Gmail labels, large mailboxes, calendars, delegated access, Google-native files, Shared Drives, mobile devices and the applications those users depend on. The pilot exposes surprises while they are cheap to fix. During the wider migration, the business runs in coexistence — some users on Google, some on Microsoft — so mail routing, calendars and file access need to keep working for everyone throughout.

DNS and Mail Cutover

The cutover moment is a DNS exercise as much as a migration one. MX records move mail flow to Exchange Online; SPF, DKIM and DMARC must be updated so the business's email continues to authenticate correctly and deliverability is protected; Autodiscover records let Outlook configure itself. Getting these records wrong — or forgetting the third-party systems that send email on the company's behalf — is one of the most common causes of avoidable disruption.

Staff Training and Support

Users are moving from Gmail labels to Outlook folders, Google Drive to OneDrive, Shared Drives to SharePoint, Chat to Teams, Meet to Teams meetings and Google's sharing links to Microsoft's. Pre-migration communications, quick-reference guides, role-based training, MFA setup instructions, mobile setup help and visible support on cutover day make the difference between a migration people accept and one they resent.

Users judge the migration by whether they can work — not by whether the migration dashboard is green.

Backup, Vault and Retention

Migration is not backup. Before the move, the business should understand what is protected in Google Workspace — including any Google Vault retention rules, legal holds or investigations, which need separate planning and cannot simply be "migrated". After the move, Exchange Online, OneDrive, SharePoint and Teams-related data need a deliberate backup arrangement: Microsoft's standard retention and recycle bins are not equivalent to an independent backup, and restore testing should be part of the plan.

When Google Workspace Can Be Cancelled

Only after validation. Historical email, calendars, contacts, files, permissions, sharing, applications and devices should be checked, failed items reviewed and business sign-off obtained before licences are reduced or the Google environment is closed. Cutover is the start of validation — not permission to cancel Google Workspace. Some businesses retain reduced Google access for a defined period as a safety net; that decision should be made consciously, not by default.

Common Migration Mistakes

• Treating the project as "copy Gmail into Outlook" and discovering the rest mid-migration
• Skipping discovery and pricing the project before understanding the data
• Copying chaotic Drive structures and over-shared permissions into SharePoint unchanged
• Ignoring Apps Script, Forms and "Sign in with Google" dependencies until something breaks
• Moving data into an unsecured tenant, or one only a supplier can administer
• Cutting DNS over without updating SPF, DKIM and DMARC
• Giving staff no warning, no training and no support on day one
• Cancelling Google Workspace before anything has been validated

How Altitude IT Support Manages the Migration

Altitude runs Google Workspace migrations through a simple method:

• Measure — assess users, data, applications, devices, permissions and current security.
• Understand — identify dependencies, risks and the correct Microsoft destination for each workload.
• Improve — secure the Microsoft tenant first, then migrate through controlled, validated phases.
• Maintain — support users, monitor the new environment and work through any unresolved dependencies.

After migration, Altitude's Operational Heartbeat can keep reviewing the things that drift over time: administrators, licences, MFA, devices, Teams and SharePoint permissions, external guests, backup, any remaining Google accounts, unresolved migration items and supplier responsibilities.

Conclusion

A Google Workspace migration is a change to how the organisation communicates, stores information, secures devices and works together. The businesses that move smoothly are the ones that treat it that way: discovery before pricing, security before data, a pilot before the masses, validation before cancellation — and proper support for the people doing their jobs through the change.

Read more about Altitude's Google Workspace to Microsoft 365 Migration service, or book a migration discovery call.