Migrate Email from Office 365 to G Suite

You want your mail in Google Workspace and retain folders, dates and attachments. G Suite is now called Google Workspace and steps match for both names. Below are three ways to migrate email from Office 365 to G Suite, what every method copies and fixes for errors that stall a move.

What moves from Office 365 to G Suite?

Both services retain mail in cloud storage but they store it differently. Office 365 uses folders and G Suite uses labels. When you move Office 365 mail to G Suite, Google converts folders to labels with matching names. A slash in a folder path becomes an underscore so A/B/C becomes A_B_C.

Google's page says its import tool copies mail, calendar events, contacts and tasks. It ignores messages over 150 MB, categories and starred status. A message that sits in two Office 365 folders is copied once so Gmail may show fewer items than Exchange did. If you only want a local copy, see how to Export Office 365 mailbox to PST.

How to move Office 365 mail with Google's Data import tool?

Google builds that tool into Admin console. It suits teams, because one CSV file maps every user. You need super admin rights in Google Workspace and a Global Administrator account in Microsoft 365.

1. Create every user in Google Workspace first so every source address has a target address before you move Office 365 mail to G Suite.
2. In Google Admin console go to Menu, then Data, then Data import & export and open Data import.
3. Next to Exchange Online select Import, then Connect.
4. Sign in to Microsoft 365 as a Global Administrator and allow pop-ups from Microsoft sites if asked.
5. With 20 users or fewer, review mappings Google finds. With more, upload a CSV file with headers Source Exchange Email and Target GUser.
6. Choose email, calendar, contacts or tasks, then set a start date. Mail sent or received after that date is copied.
7. Select Start import to move Office 365 mail to G Suite. Counts update live and Google emails you a report when it finishes.
8. After a first pass, start a delta import to finish your Office 365 to G Suite move and retry failed items.

Menu names above come from Google's own admin guide. Admin screens differ so confirm them in your console. One import takes up to 1,000 users and a CSV under 10 MB so split a larger company into two batches.

How to move Office 365 mail to G Suite with Outlook?

For one or two mailboxes you can move Office 365 mail to G Suite in classic Outlook for Windows. Both accounts open side by side and you copy folders yourself.

1. To move Office 365 mail to G Suite here, sign in to your Office 365 mailbox in classic Outlook.
2. Select File, then Add Account and add your Google Workspace address. Sign in on Google's own window.
3. Wait for both mailboxes to finish syncing so you move Office 365 mail to G Suite with every message.
4. Select an Office 365 folder, drag it onto your Google Workspace mailbox and drop it there.
5. Repeat for every folder to move Office 365 mail to G Suite and compare message counts on both sides.

Outlook downloads mail first and uploads it after so large folders are slow. It copies one folder at a time and has no filters or report. Moving other accounts into Google as well? See how to Migrate IMAP to Gmail.

Steps to move Office 365 mail to G Suite with software

1. Install Corbett Email Migration Tool on your Windows PC and open it with Run as administrator.
2. Choose Microsoft 365 as source for your Office 365 to G Suite move and sign in on Microsoft's own consent screen.
3. Choose Google Workspace as destination and approve access on Google's consent screen.
4. Tick Office 365 folders to move and untick Junk Email and Deleted Items. Message counts show size up front.
5. Add date, sender, subject or attachment filters if you want to move Office 365 mail to G Suite in smaller parts.
6. Start the transfer, then open a CSV report saved at its end.

Many users? Add source and destination pairs from a CSV file, one row per user and it processes them one after another. A dropped connection resumes your transfer and duplicate emails are ignored. Contacts, calendars, tasks and notes travel with mail where your source account holds them. It does one cutover per task, with no scheduler and no incremental sync so a second pass copies your full selection again. Licence is lifetime from $99 with a 30-day money-back window. To retain a file copy of Office 365 first, use Corbett Office 365 Backup Tool, which saves a mailbox as PST, MBOX, EML and more.

What do you need before the move?

Check these items first, because most stalled moves trace back to one of them.

• A super admin account in Google Workspace and a Global Administrator account in Microsoft 365.
• Google Workspace users created with Gmail and Calendar switched on.
• Source addresses that match your CSV file and carry a valid Microsoft licence.
• A start date so you do not copy years of old mail when you move Office 365 mail to G Suite.

Plan your DNS switch last when you move Office 365 mail to G Suite. Retain MX records on Microsoft 365 until import finishes, then point them to Google so new mail arrives in Gmail. Need to move users between Microsoft tenants instead? See how to Migrate Office 365 account to another account.

Which way suits your Office 365 move?

To move Office 365 mail to G Suite for a company, start with Google's Data import tool if you are an admin. Use Outlook for one mailbox. Use software when you want folder tick boxes, filters and a report without admin setup.

Want a personal inbox instead? See how to move Office 365 email to Gmail. For Gmail to Gmail, see how to Migrate Gmail emails to another Gmail account.

Why does the Office 365 move to G Suite fail?

Import will not start to G Suite

Google says a super admin must start imports, because it grants domain-wide delegation. Confirm "Data Import" shows as an authorized API client under Domain-wide delegation.

Needs permission to access resources

Sign in to Microsoft with a valid Global Administrator account. A normal user cannot connect Exchange Online to move Office 365 mail to G Suite.

User not found or mail service not enabled

Create your Workspace account and switch on Gmail and Calendar. Check that source addresses match your list and carry a valid licence. Google says to wait a few hours and retry if that error remains.

Fewer emails after the move to G Suite

Exchange counts a message once per folder, while Gmail uses labels. Compare Emails imported with Emails discovered in import logs before you assume mail is lost.

Why IMAP migration in Microsoft 365 admin center fails here

Some older posts tell you to use IMAP migration in Microsoft 365 admin center. That tool moves mail into Microsoft 365, not out of it so it cannot move Office 365 mail to G Suite. Use Google's tool or software to move Office 365 mail to G Suite. No public forum thread matched Exchange Online to Google Workspace errors so fixes above come from Google's own troubleshooting page.

What to do after the move?

After you move Office 365 mail to G Suite, open Gmail for a few users and compare label counts with Office 365. Start a delta import to catch late mail. Then switch MX records, tell users to sign in to Google Workspace and retain your Office 365 mailboxes until you are sure. Microsoft deletes a mailbox 30 days after its licence is removed, according to Corbett's Office 365 page so retain a backup first.

Questions about move Office 365 mail to G Suite