Things to Know When Migrating From G-Suite to Office 365

Say Goodbye to Google Apps

Any IT admin leaving Google’s G-suite for Microsoft’s Office 365 knows that there are some significant variations between these two software-as-a-service (SaaS) productivity platforms.

As a result, migrating records from Google to O365 requires some careful planning that may not be explicitly addressed in the official Microsoft Office 365 Onboarding Guide.

To ensure your G-Suite records isn’t misplaced in translation, we’ve outlined the great practices for managing the migration from G-suite to Office 365. This information will help you avoid the frequent pitfalls and troubles associated with G suite to Office 365 migrations.

Scoping Your Migration

Before you begin a migration between Google’s G-Suite and Microsoft’s Office 365, you’ll need to answer 4 key questions.

Your answers to these questions will determine the type and scope of your migration. Having these answers firmly in place earlier than the migration system begins will stop issues down the road.

Migrating Email, or Everything?

Let’s be honest: most migrations to Office 365 are all about Microsoft Outlook. Some businesses simply can’t live without the world’s most well-known desktop email application. As such, many G-Suite to Office 365 migrations are simply Gmail to Outlook and Exchange online migrations. This is doubly true in mixed-vendor environments where OpenOffice is used as an alternative of Google Docs, or Box or Dropbox are used instead of Google Drive.

Bottom line: are you transferring everything to Office 365, or just your email solution? If you’re moving more than email, is all of it coming out of Google Apps, or does data need to be migrated from additional platforms? Be certain you comprehend the answers to those questions earlier than you commence your migration. You’d be amazed how regularly unique locations, departments, or even individuals use alternate software that IT didn’t recognize about. Otherwise, you will run the risk of leaving data behind.

Each migration tool has a related set of costs and compatibilities to consider, but you need to be very clear about which tools you’re going to use before migration starts.

What’s in Your Migration Toolbox?

There are variety of software tools and services for a Google Apps to Office 365 migration. These solutions vary from free applets that simply do IMAP transfers between Gmail and O365 mail accounts, to complex SaaS tools that map and move data between Google accounts and Active Directory-managed Office 365 users. Each migration tool has a related set of costs and compatibilities to consider, however you should be very clear about which tools you’re going to use before migration starts.

What should be Your Migration Timeline?

Unless you can count the number of G-Suite customers in your Google domain on two hands, it’s unwise to migrate everyone over to Office 365 at the same time (and it’s probably a bad thought even for domains of less than 10 person accounts.) Migration should happen in waves, and begin with a pilot subgroup of early adopters. If possible, break up your migration into at least three stages — typically ten percentage of customers in the first wave (sometimes referred to as the pilot wave), forty percentage of user accounts in the second, and the last 50 percent in the third — and leave adequate time between each stage to troubleshoot any troubles observed at some stage in each phase. By putting a clear, realistic timeline before your migration starts, you’ll avoid countless complications in the future.

Identifying Data That Can’t Be Migrated

Migrating Email, or Everything?

Office 365 and the G-Suite are comparable SaaS productivity suites, however not every Google Apps data element has a counterpart in O365. Some items are not reasonably handy or exportable from Google Apps, and a noteworthy percentage of G Suite data and metadata simply can’t be imported into Office 365. This information will have to be manually transferred, modified, and/or abandoned during migration – and both you and your users need to be prepared.

Non-Classic Google Sites

In November of 2016, Google introduced a fully redesigned version of Google Sites with new templates and features. Unfortunately, when they revamped Sites, Google did not include the new system in their standard Google Drive REST API, which most migration tools use to extract data from Google Sites for import in Office 365 SharePoint Online.

By the same token, Google Sites created with legacy versions of Google Apps – the free versions of Google Apps that were retired in December 2012 – are additionally excluded from the Drive API. Thus, almost any Google Site created before December of 2012 or after November of 2016 is not easily migrated, and IT administrators should decide if their migration tools and services have a workaround for migrating this Sites data.

“Muted” Gmail conversations

The muted status of a Gmail conversation — where follow-up reply-all messages to team e-mail strings are immediately marked as read and archived — can’t be migrated to Office 365 Outlook online. All the muted responses in the thread will be migrated, so no information is lost, however future reply-all responses made after the migration will not be muted. Users have to be prepared for replies to previously muted email conversations to suddenly appear in their inboxes again.

Files Larger Than 15GB

Microsoft Office 365 OneDrive for Business supports a maximum file size of 15 gigabytes. G Suite Google Drive helps a maximum file size of 5 terabytes. If your Google Drive customers usually store large multimedia files that exceed 15GB in size, you’ll want to stock these and decide to keep them outside OneDrive, as they will be incompatible with Office 365 today.

Individual Email Signatures

Both Google Apps Mail and Outlook online allow for the management of standardized email signatures, and the migration of standard signatures can frequently be handled through mature migration tools and services. Individual e mail signatures, personalized to a single Gmail user, are not programmatically accessible via IMAP or the Gmail API. As such, individual signatures often cannot be migrated by standard tools and services, and thus need to be explicitly addressed by migration administrators.

Gmail Filters

While Outlook regulations are nearly the identical as Gmail filters, enough variations exist that Gmail filters frequently cannot be directly migrated or, more accurately, translated – into Outlook. IT administrators should observe what Gmail filters can be converted to Outlook rules, and how to train users on recreating filters that did not survive the migration to Office 365.

Migration Policies

When you migrate data from G Suite to Office 365, your policies around that data move, too. IT administrators should lock down their processes and policies around the scenarios outlined below before initiating a Google Apps to O365 migration.

Migrated Vs Archived Data

Some data may not need to be migrated from your G Suite domain to Office 365, as it is no longer business-critical, but your organization may be required to maintain it for compliance purposes. In worst cases, this includes Google Apps user accounts that exist merely for reference purposes, still incurring annual licenses fees long after the actual user has departed the company.

Advanced Threat Protection Settings

The Office 365 version of Exchange offers Advanced Threat Protection, which is the O365 counterpart of Gmail’s Enhanced Pre-Delivery Message Scanning and other anti-phishing and anti-spam features. Migration administrators should review the available options and adapt your previous e mail security policy for Microsoft’s O365 feature set.

During your migration, messages, documents, and data will exist in two systems simultaneously – a situation that may persist for weeks or months.

Calendar Resource Reservations

It may seem petty, but nothing sours users on a system migration faster than a fight over conflicting conference room reservation.

During your migration, some users will still exclusively operate in G-Suite even as others have transitioned to Office 365, which means they’ll be reserving conference rooms, audio/visual equipment, and other shared calendar resources in two different systems. IT admins need a process for syncing this data in order to avoid confusion and frustration over double-booked rooms and equipment.

Spam and Trash Folders

Gmail has a Spam folder, and both Gmail and Google Drive have Trash bins, and all of them may include data that was either inadvertently disposed of, or that must be maintained for compliance reasons. IT administrators must have a firm grasp of how much Spam or Trash data will be migrated from G-Suite to Office 365.

Developing Your Migration Failsafe

As users are migrated from one environment to another, avoid paying for both solutions’ licensing prices by having a copy of their data to fall back on outside of the app itself.

The most necessary phase of your migration plan is your failsafe planning. No matter how skilled or sophisticated the tools, services, plan, and staff involved in your G-Suite to Office 365 migration, data can still be lost. In some cases, the original Google Apps data is inadvertently destroyed as it fails to load top into Office 365.

How do you ensure data is not corrupted or deleted during the migration?

Backup Your Original G-Suite Data

Before you start moving data out of the G-Suite, make sure you have a full third-party backup of all your Google Apps data. It’s up to you to ensure that no matter what havoc migration tools may wreak on your G-Suite systems, you’ll always have a clean, reliable backup you can restore to the original Google domain.

Some migration tools actively remove data from G-Suite to ensure that, once it “arrives” in Office 365, there are not two competing copies of the same messages, documents, or files. This practice guarantees that there is always a single system of record for any individual user. Unfortunately, this practice can be problematic if G-Suite data is corrupted during the switch to Office 365.

IT administrators should have firm plan in place for calling off a migration and restoring full functionality to Google Apps.

Rollback Plan

Some migrations simply don’t work out. Perhaps it’s simply impossible or impractical to recreate old G-Suite business processes in Office 365. Perhaps the time and effort required to re-train end users on Office 365 is more difficult than would justify a migration. Or possibly your IT department has absolutely encountered a new, unexpected set of priorities that make migration impractical at this time. Whatever the reason, IT administrators must have firm plan in place for calling of a migration and restoring full functionality to Google Apps.

That almost certainly means having reverse-migration tools, apps and services that can move data out of Office 365 and into G- Suite – as well as a full, easy to restore, backup of your original data for direct restoration into Google Apps if necessary. While it may seem tedious to plan for undoing the same migration you’re already outlining, having this failsafe in place ensures that a failed migration doesn’t become an outright data disaster.


Migrating from Google’s G Suite to Microsoft Office 365 is a fairly simple process for a skilled IT professional but – as with all complex tasks — the devil is in the details. This guide outlines some key areas where data, metadata, and IT policies don’t directly translate between Google Apps and O365. By breaking your migration down into manageable stages, addressing the areas of data and process incompatibility mentioned above, and being responsive to the have an effect on of the project on your users, IT administrators can ensure that their G Suite to Office 365 migration is a success.

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