How to Migrate Gmail to Microsoft 365 in 2026: Step-by-Step Guide

Why Do Business Users Migrate From Gmail to Microsoft (formerly known as Office 365)?

These are the common scenarios due to which organizations move data from Gmail to O365.

Deeper Microsoft ecosystem needs	Mergers & Acquisitions	Compliance & Governance requirements
Domain or infrastructure changes	Client or partner expectations	Better scalability for larger teams

Which Native Method Must You Opt For to Move from Gmail to Microsoft 365?

There are two native methods for the migration: IMAP Migration & Microsoft Google Workspace Migration. Use the native IMAP migration method in the Exchange Admin Center for mail-only transfers. Or use the Google Workspace automated migration path if you also need to move calendars and contacts.

IMAP migration moves email only. It’s fast to set up and doesn’t require much beyond mailbox access, but it leaves contacts, calendars, and tasks behind entirely.

To perform Google Workspace migration (run through the Exchange admin center) goes further, pulling across mail, contacts, and calendar items. Microsoft treats Gmail mailbox migration and Google Workspace tenants as a separate workflow, as explained in Microsoft Gmail migration documentation. It’s more capable, but it also asks more of you: API configuration, service account setup, and correct permissions on both the Google and Microsoft sides before anything starts moving.

Where the Native Methods Struggle

Both approaches get the job done in narrow scenarios, but they come with real friction points worth planning around:

• IMAP handles mail and little else – anything beyond that needs the fuller Workspace method.
• Large mailboxes, high item counts, and Google-side throttling can slow migrations down considerably.
• Admins need to pre-configure Workspace and Microsoft 365 settings, APIs, and user mappings correctly, or batches fail partway through.
• Some Google data types simply aren’t supported no matter which native method you pick.
• Filtering, folder mapping, and duplicate handling are limited compared to purpose-built tools.
• Verifying migrated data and resolving failed items still falls on the admin — native tools don’t do this for you.

Running a Gmail to Microsoft 365 Migration with Microsoft’s Native Tools

Microsoft doesn’t give you one path here – it gives you two, and mixing them up wastes time. IMAP handles mail and nothing else. The Google Workspace route brings mail, calendars, and contacts along with it. Figure out which one your users actually need before you start setting anything up, because switching mid-project means redoing your connection work from scratch.

Moving Mail Only with IMAP

IMAP migration is the lighter-weight option, & you’ll run it from the Exchange admin center.

• You need global admin rights. IMAP migrations can only be run by someone with global admin access in Microsoft 365.
• Every user needs a mailbox and the right license. A mailbox alone isn’t enough; it also needs a license tied to an Exchange Online plan before mail can land in it.
• Your domain has to be verified. Add a TXT record to prove ownership, or fall back on the default yourcompany.onmicrosoft.com domain if you’re not ready to verify yet.
• Gmail needs prep work too. Each account owner has to generate an app password, and 2-step verification must be switched on for the users being migrated.
• You’ll need a properly formatted CSV. It has to use the exact column headers, EmailAddress, UserName, and Password in columns A, B, and C, and stay within 50,000 rows or 10 MB, whichever limit is hit first.

Once that’s sorted, set up a migration endpoint, mark IMAP as the migration type, & create your batch. There’s no rule saying you have to move every user in one go – splitting the work by department, priority level, or risk tolerance is usually the smarter play. (Microsoft Learn)

What Native Migration Tools Leave Behind

Every migration method has edges, and it pays to know where they are before cutover day turns into a support queue full of confused users. Here’s what typically doesn’t survive the trip when you rely on Microsoft’s built-in options to move from Google Workspace to Microsoft 365.

IMAP’s gap is simple: calendars and contacts stay put. This isn’t a bug or an oversight — IMAP was never built to carry that kind of data, so it’s excluded by design. (Microsoft Learn)

The Google Workspace path covers more ground but still has holes:

• Shared calendars and any custom event colors get dropped.
• Contacts are capped at three email addresses each – anything beyond that gets trimmed.
• Gmail-specific extras like tags, contact URLs, and custom labels don’t carry over.
• Rules do migrate, but they arrive switched off. Someone needs to check them in Outlook and turn them back on manually.

A handful of environment and policy quirks are worth flagging too:

• This migration path isn’t an option at all for Office 365 GCC High or DoD government tenants.
• Individual messages are capped at 35 MB by default.
• Any retention or archival policies should be turned off beforehand – leaving them active tends to make migrated items show up as “missing” even when they aren’t.
• How fast contacts and calendars move depends heavily on the quota tied to your Google service account, not just your Microsoft 365 setup.

Gmail Labels vs. Outlook Folders: A Mismatch Worth Planning For

Gmail organizes mail with labels. Outlook uses folders and categories instead. They sound similar but behave differently, and treating them as interchangeable is where migration headaches usually start.

A Gmail message can hold several labels at once. Outlook doesn’t work that way. Force those labels into folders, and the same email can end up duplicated across multiple locations, bloating the mailbox. Push them into categories instead, and everything stays lumped in the inbox — users lose their familiar folder structure and start asking where it went.

Most users expect a clean one-to-one swap: their labels becoming folders exactly as they were. When “Project Alpha” or “Q4 Reviews” doesn’t show up in the folder pane afterward, confusion follows fast. The fix isn’t technical – it’s communication. Decide on your mapping approach ahead of time and tell users what to expect before cutover, not after.

Not every label is worth carrying over. PowerShell’s -ExcludeFolder option lets you skip clutter you don’t need in the new environment. Trimming the excess before migration often makes for a cleaner landing than moving everything as-is.

How Cigati Helps to Migrate Personal Gmail to Office 365

The Google Workspace Backup Tool helps users back up & migrate data from Google Workspace. It can handle Gmail, contacts, calendars, & Google Drive data, which makes it useful for enterprise users. If you want to export your Gmail to Outlook, you can also go through our detailed guide on export Gmail Emails to Outlook easily.

Key Capabilities for Gmail to Office 365 Migration

Bulk Migration through CSV import	Selective Migration	Duplicate Handling Feature	Multithreading Processing for Faster Runs
Secure Authentication	Folder & Metadata Preservation	Resume Capacity	Google Drive Migration
User Mapping	Detailed Migration Reports	Free Up Server Space	Attachment Handling

Look at the steps for how the Cigati Gmail to Office 365 Migration Tool moves data from Gmail to O365.

Which Migration Method Should You Choose?

1. Only need email >> use IMAP method may be sufficient
2. Need email + contacts + calendars >> Google Workspace Migration
3. Large-scale migration + Google Drive >> Cigati Gmail to Office 365 Migration Tool

What Data Can You Migrate From Gmail to Office 365?

Gmail / Google Data	Can it be migrated?	Destination
Emails	Yes	Exchange Online
Attachments	Yes / API limits	Outlook
Gmail labels	With mapping / limitations	Outlook folders / categories
Contacts	Yes, it depends on the method	Outlook People
Calendars	Yes, it depends on the method	Outlook Calendar
Google Drive	Separate Migration	OneDrive / SharePoint
Google Tasks	Method-dependent	Microsoft equivalent

If your organization only cares about email, the simplest native route may be enough. But most teams eventually need contacts and calendars too – and that changes which method makes sense.

Pre-Migration Checklist

• List all users, mailbox sizes, shared accounts, contacts, & calendars that need to be moved.
• Identify important labels and understand how they will be represented in Microsoft 365.
• Find large messages and attachments that may affect migration time or require special handling.
• Create the required accounts and assign the appropriate licenses.
• Add & verify the organization’s domain in Microsoft 365 before the final cutover.
• Make sure destination mailboxes are active and ready to receive migrated data.
• Confirm administrator access, authentication, API settings, and required migration permissions.
• Migrate a small group of users first to identify configuration or data-mapping issues.

How to Handle Gmail Labels During Migration?

Gmail labels work differently from Outlook folders, so the mailbox structure may change after the migration process. After that, a single Gmail email can have several labels, while Outlook generally organizes messages into folders.

Before migration, review the label structure and identify important labels and nested labels. Map them to suitable Outlook folders where possible. Also check Gmail system folders because they can sometimes result in duplicate messages during IMAP migration.

After migration, users should understand that their Gmail labels may not look exactly the same in Outlook. Also, a quick review of the migrated folders & sample emails can help confirm that the important messages are in the expected locations.

Common Problems Occur When Migrate Gmail to O365

A migration problem may arise even after the correct initial setup. Missing emails, incorrect folder mapping, authentication failures, & slow migration are some of the issues administrators may encounter.

Problem	Possible Cause	Solution
Gmail emails are missing after migration	This migration may not have included all Gmail folders or labels. With an IMAP-based migration, only supported mail folders are transferred. Gmail’s label structure can also affect how messages are exposed through IMAP. Microsoft notes that IMAP migration does not transfer contacts, calendars, or tasks.	First, you have to compare the source & destination mailboxes. Check the Gmail labels and folders that were included in the migration. Review the migration report for skipped or failed items & check whether the affected messages are present under another folder in Microsoft 365. If the migration method has data-type or folder limitations, use a method that supports the required Gmail data.
Contacts are missing	Email migration and contacts migration are not necessarily handled by the same process. Microsoft specifically lists contacts as data that is not transferred through an IMAP migration.	Confirm whether the migration method supports contacts. If it does not, export or migrate the contacts separately through a supported method. After importing them into Microsoft 365, verify names, phone numbers, & other important contact fields.
Some Attachments were not migrated	The affected message may exceed the migration method’s supported message size, or the item may have failed during synchronization. Microsoft documents a 35 MB maximum message size for its IMAP migration process.	Check the migration report for failed or skipped messages. Identify whether the missing attachments belong to messages that exceed the supported size or contain an unsupported item. For important mailboxes, compare a sample of large messages between Gmail & Microsoft 365 before completing the migration.

Best Practices for Gmail to Microsoft 365 Migration

• Make sure to audit before migration
• Map users before copying data
• Migrate in controlled batches
• Keep the source environment available temporarily
• Communicate label/folder changes to users
• Always monitor migration reports

Gmail to Microsoft 365 Migration: Native Tool vs. Migration Software

Factor	Native Microsoft Tools	Migration Software
Email Migration	✔️	✔️
Calendar/Contact Migration	Method-dependent	✔️
Bulk Processing	✔️	✔️
User Mapping	Manual configuration	✔️
Filters	Limited	Advanced
Incremental Migration	Available depending on method	Usually Available
Detailed Report	Limited	Complete Report-Folder-Wise
Google Drive Migration	Separate Process	Tool-dependent

After Migration, Change DNS

Remember this: you must change your DNS after the completion of migration. Make sure you update your DNS and MX records. If you face any difficulties then contact our support team.

Conclusion

Getting Gmail data into Microsoft 365 cleanly comes down to matching the method to the job — IMAP for simple mail moves, Google Workspace migration when calendars and contacts matter too, and a dedicated tool like Cigati’s Google Workspace Backup Tool when Drive files, scale, or reporting are part of the picture. Rushing setup or skipping the pre-migration checklist is where most projects run into trouble. Test with a small group & the switch to Microsoft 365 stays manageable rather than chaotic.

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