How to Migrate G Suite to Office 365 Step-by-Step

G Suite to Office 365 migration is a task which, if performed incorrectly, can lead the company to critical data loss.

To make the migration smooth and not lose critical data along the way, you need to take care of the following things:

  • Backup your files
  • Define data that can’t be migrated and what to do with it
  • Determine what policies (i.e. Litigation hold) are applied to the data you migrate

Let’s take a closer look at these, and a bit later we’ll show you how to migrate G Suite to Office 365 step-by-step.

3 Must-Dos to Migrate From Google Apps to Office 365

As you’re reading this, you probably don’t have the luxury of hiring a data migration consultant to walk you through the possible pitfalls. So before you start transferring data, be sure to consider these three things:

Backup your G Suite data

If you somehow managed to work around backing up your data till this moment, now is the time to take care of it.

Backing up your data is crucial because:

-Backup protects your data from accidental and intentional deletions and ransomware;

-You can use backup as a cheaper version of Google Vault or O365 Litigation Hold (more on this read below);

-It makes any data migration easier and safer;

-You can restore data in terms of minutes.

The data migration process is always coupled with data loss possibility. Even when you use professional SaaS solutions to map and transport all the files, there is a risk that critical data will be lost in migration and be gone for good.

To avoid this scenario, get started with the migration only after you created a backup for your G Suite data! When you are done with the migration, make sure to keep backing up your Office 365 data regularly to avoid data loss due to ransomware or human error.

To backup your G Suite data you can use our backup service Spinbackup, which works with both G Suite and Office 365 platforms. 

Get Free 15-Day Trial

Identify data you can’t transfer to O365

There is G Suite data that simply don’t have the analogy in the Office 365 environment. Therefore, the G Suite migration tool will not process them.

This data includes the following:

  • Google Sites created before 2012 and after 2016
  • Mail: Vacation Settings or Automatic reply settings, email signatures, Filters, Rules.
  • Meeting Rooms: Room bookings.
  • Calendar: Shared calendars, cloud attachments, Google Hangout links, and event colors.
  • Contacts: The limit is three email addresses per contact; Gmail tags, contact URLs, and custom tags.
  • Files that are larger than 15 GB.

So, how can you transfer this information then? There are three options: to migrate every piece of such information manually, to modify it, or to abandon it. The choice will be unique in any particular situation and should be agreed upon with the data owner first.

Check the policies applied to the data

Some data in your organization may be a subject of specific policies, like retention policy or litigation hold. That is usually dictated by the compliance requirements your company has to meet. It often makes companies keep data that isn’t business-critical (i.e., ex-employees emails) but still relevant for possible investigations.

Here are the two things to take care of before the migration:

1. Decide what to do with data that have no value for the company but has to be kept for legal reference. Legal hold, both in Google and in O365, is included in the most expensive subscription plans, making it unreasonable to pay around $12/month per account for keeping that data. Using Spinbackup for these purposes would be the most cost-effective option to save the archived data without migrating them to the new O365 account.

Read how you can save up to 64% on G Suite (and O365) licenses in this article.

2. In all the other active accounts in which data fall under the litigation hold, make sure to enact the Office 365 Litigation Hold. It includes all the accounts of the current employees that have the Google Vault enabled.

Data migration from to G Suite to Office 365

In April 2019, Microsoft created the G Suite migration tool to help G Suite users with the data migration to Office 365 cloud. This highly-customizable tool helps you to migrate data. It is possible to migrate one user or a whole company.

To perform the data migration from G Suite to Office 365, you need to do several things.

Create a Google Service Account

1. First of all, go to the Developer page for Service Accounts and sign in. We recommend using the Google Chrome browser.

2. Fill down the details about the new project and click Create.

3. In Create Service Account find Service account name. Type in the name and click Create.

4. In the Grant users access to this service account section click Create key.

5. You will be given two key type options. You need JSON. Ensure it is selected and click Create.

6. Click Email in the Service Account. On the Service account details page, you’ll find Unique ID. You’ll need the ID later.

7. Tick the box Enable G Suite Domain-wide Delegation, if you see it (if you don’t see it, it is enabled).

Enable API

1. Go to the Developer page to set up an API.

2. Select the project you created.

3. Enable the APIs you need. You may enable one API (for example, Gmail API) or several.

Grant Access to the Service Account

1. Go to your G Suite Admin panel. Click Security. Find Advanced settings and click Manage API client access.

G Suite Migration API

2. In Client Name, type the ClientId for the service account you created.

3. In API Scopes add the required scopes (,,, They should be comma-separated, without spaces.

4. Click Authorize. Ensure, that the list shows correct items. For example, “Email (Read/Write/Send)” and However, the settings may take a significant amount of time (up to 24 hours) to propagate.

Create a Sub-domain for Mail Routing to Office 365

1. Go to your G Suite Admin panel. Select Domains. Click Manage domains.

2. After that, click Add a domain or a domain alias.

G Suite to Office 365 domain

3. Select Add another domain. Enter a name for the domain you will use for routing your emails to Office 365. Note this name, as you’ll need it later. We recommend creating a sub-domain of your primary domain so that verification will go faster. When you’ve entered the domain name, click Continue and verify domain ownership.

4. Ensure your domain is verified. If you selected a sub-domain name, it will be verified automatically. Click Skip Google MX setup. After that, click I use another mail server (the new server is Office 365).

5. Log into your DNS provider and update your DNS to have an MX record at the domain you created. Follow the Add a domain to Office 365 guide to add your Office 365 routing domain and configure DNS.

Create a Sub-domain for Mail Routing to G Suite domain

1. Go to your G Suite Admin panel. Select Domains. Click Manage domains.

2. After that, click Add a domain or a domain alias.

3. Select Add a domain alias of your domain name. Enter the domain that you will use for routing your emails to G Suite. Create a sub-domain of your primary domain so that verification will go faster. When you’ve entered the domain name, click Continue, and verify domain ownership.                                                                                                                                    4. Ensure your domain is verified. If you selected a sub-domain name, it will be verified automatically. After that, click Set up Google MX records and follow your DNS provider.

Provision users in O365

Once your G Suite environment is configured, you can complete your migration in Office 365 Exchange admin center. Before the migration, ensure all MailUsers have been provisioned for all users migrating from the G Suite. If users aren’t provisioned, provision them. To do it, follow the instructions here.

Create a G Suite migration batch with the Exchange admin center (EAC)

1. Go to your Office 365 Admin center. Click Exchange (you’ll see this button on the left, among other admin centers).

2. Select Recipients. Then select Migration and click New (plus). You’ll have two options. Choose Migrate to Exchange Online.

Migration with Office 365 Exchange Admin Center

3. You will see the New Migration Batch window. Select G Suite (Gmail) migration. Click Next.

office 365 G Suite migration batch

4. Now you need to create the .csv file. This file is a list of users you need to migrate. The file should have the EmailAddress header and all emails. Optionally, you can have the Username list in the file. If you have other columns you want to add, tick the Allow unknown columns in the CSV file box. 

5. Click Choose File and open the file you’ve created. After that, click Next.

6. Enter the email address of a G Suite user.

7. Find the Specify the service account credentials using the JSON key file section. Click Choose File to select the JSON file. Open the file. On the new migration batch page, click Next.

8. Enter the New migration batch name. Enter the Target delivery domain name. This domain is the one you created before for routing G Suite mail to Office 365. If you need to, you can specify other settings, such as Bad item limit. After that, click Next.

9. The next page helps you to customize the new batch. For example, you can choose the recipients, who will get the report about the batch. Also, you need to select the options of the start and the end of the batch. After everything you need is selected (do not forget to double-check!), click new.

10. Go to the Exchange admin center, select recipients and migration. You will see your batch and its status. Wait until the status is Synced to complete the batch manually (or it will be completed automatically, depending on the options selected). Ensure the batch status is Completed. 

The G Suite to Office 365 migration is completed! Mails, coming to the old Gmail addresses of the migrated users, will be sent to the new Office 365 addresses as well.

To secure your data in O365, check out the article How to protect Office 365 data from ransomware. 

This website stores cookies on your computer. These cookies are used to improve your website experience and provide more personalized services to you, both on this website and through other media. To find out more about the cookies we use, see our Privacy Policy. We won't track your information when you visit our site. But in order to comply with your preferences, we'll have to use just one tiny cookie so that you're not asked to make this choice again.Learn more