Office 365 Migration Guide

Planning an Office 365 migration

You're Not Alone

More and more organizations are adopting Microsoft Office 365 and its back-end identity system, Azure Active Directory (AD), along with related cloud applications like SharePoint Online and Exchange Online. In fact, Microsoft reports 135 million monthly active commercial users of Office

365 and over 10 million tenants of Azure AD. It also notes that more than 200,000 organizations and 190 million people are using SharePoint for intranets, team sites and content management. Those numbers are projected to continue growing at a fast clip; for example, the number of Office 365 users is expected to more than double by 2019.

A couple of factors are driving this strong adoption curve. For one thing, some very popular legacy on-premises systems are coming off of mainstream support; for instance, mainstream support for Exchange 2013 ended April 10, 2018. Other organizations are turning a merger or acquisition into an opportunity to modernize their environment and satisfy the needs of their 21st-century workforce.

The Benefits of Office 365 And Azure AD

As organizations evaluate their options, Office 365 and Azure AD often rise to the top of the list. Office 365 has matured into a fantastic collaboration cloud platform that delivers stability, flexibility and high availability to drive productivity, along with the security and compliance organizations require today. Moreover, Office 365 applications now boast feature sets on par with their on-premises counterparts. It's really hard to justify investing in on-prem email, collaboration and communication capabilities — and all the

supporting infrastructure and support — when you can get everything you need from a monthly subscription to Office 365.

Azure AD adds some compelling features of its own, such as the ability to provide single-sign on (SSO) to thousands of end-user applications, including non-Microsoft applications like Salesforce. Plus, it offers many valuable security features, like conditional access policies that make it easy to grant just-in-time administrative access to certain pieces of Azure AD and Office 365.

Plus, moving to the cloud enables you to take advantage of applications like SharePoint Online and Exchange Online. SharePoint Online, for example, delivers unparalleled collaboration capabilities, including cloud storage for each user in OneDrive, the ability to securely share content with people both inside and outside your organization, easy content management, team and communication sites, advanced data-loss prevention (DLP) capabilities, search and eDiscovery.

It's really no wonder so many organizations have moved to these cloud technologies, and that many more are eager to migrate.

The Challenges of An Office 365 Migration

Office 365 is an appealing destination, but getting there is no stroll in the park. At a high level, the challenges are the same as with other migrations: doing a proper assessment, inventory and cleanup of your source environment; performing the migration efficiently and tracking its progress; making certain that users can work normally throughout the migration process; ensuring you can properly manage your target environment afterward; and, of course, communicating effectively with users throughout the process.

Following best practices and choosing the right tools will help you ensure a smooth and successful Office 365 migration.

Specific challenges include trying to map permissions from your source platform to Office 365; dealing with feature restrictions and size limitations; getting a complete inventory of SharePoint applications and data spread across multiple farms; and migrating highly customized SharePoint applications. Moreover, the native tools have important limitations during every phase of the Office 365 and Azure AD migration process; for instance, there's no native capability to merge tenants, or to migrate from one tenant to another.

Do's and Don'ts for Overcoming These Challenges

But with the right knowledge and the right tools, you can meet all of these challenges gracefully. In this ebook, we'll explore five critical best practices that will help you ensure a smooth and successful Office 365 migration:

  • Don't skimp on preparation.
  • Do plan for co-existence.
  • Do minimize the impact on the business.
  • Do implement the ABCs of security.
  • Don't forget about post-migration management.

Then we'll touch on how specific Quest® solutions can simplify and streamline the entire process — from pre-migration planning through migration and coexistence to post-migration management of your new environment.

Don't skimp on preparation

Proper preparation will help you deliver a faster migration with far fewer issues, as well as a cleaner target environment that's easier to manage and secure.

"Give me six hours to chop down a tree and I will spend the first four sharpening the axe," Abraham Lincoln once said, and that's sound advice for any migration. Taking the time to prepare carefully will easily pay for itself — you'll get a faster migration with far fewer issues, as well as a cleaner target environment that's easier to manage and secure. Here are the key questions to make sure you get answers to during the preparation phase:

What's in my current environment?

Getting an accurate inventory of your source environment is a critical first step in any migration. Start with the basics, such as user accounts, logon names and email addresses; SharePoint content, information architecture, web parts and solutions (especially all customizations); and the number and size of Exchange mailboxes and public folders. But also be sure to think about how you're doing your security administration and what permissions and delegations you have in place. And be sure to discover all your file shares, email archives and offline PSTs and determine who owns them so you can assess their purpose and value.

One important tip is to start early on your application inventory, because if critical apps won't work on your target platform, you might have to reconsider doing the migration at all. Don't just list application names; dig down and document details such as versions and configurations.

Some of this discovery will be done through conversations with your business counterparts, but a lot of it requires interrogation of IT systems. Keep in mind that gathering and manipulating the data with native tools will be time consuming and require scripting expertise; third-party software can streamline the work significantly, and also deliver more complete and accurate results.

Start early on your application inventory, because if critical apps won't work on your target platform, you might have to reconsider doing the migration at all.

What are the expectations for the target environment?

Knowing your goals for your Office 365 environment will inform many decisions about the migration. Consider what data and applications you want to host there, and don't move forward without clarity from the business about what the user experience should look like.

What exactly is in scope? Is there anything that can't go to the cloud for governance, compliance or technical reasons?

Think hard about what should get moved and what shouldn't. For example, there might be sensitive data that needs to stay on premises or applications that can't work with mailboxes in the cloud.

Is any remediation required before the migration?

Clean up your current environment before you begin migrating anything. After all, migrating things you no longer need or that shouldn't be moved will slow your migration unnecessarily, increase the risk of issues, and cause headaches in the new environment. Many organizations also need some AD restructuring or consolidation; if you've been putting that off,

tackle it before starting your migration. Similarly, review your SharePoint site metrics to understand how SharePoint is actually being used, so you can assess which sites and content might need to be reorganized before migration.

Can we recover quickly from any issues during the migration?

Accept that even the best planning and preparation cannot guarantee a completely issue-free migration. You might migrate something you shouldn't, or move it before users are ready. Maybe a third-party Outlook add-on did something strange to mail items, interfering with their migration. Or you might encounter unexpected name resolutions or trust behavior. You should be prepared for the possibility that something will go wrong and ensure that you can quickly roll back any unwanted changes during the migration.

Even the best preparation can't guarantee an issue-free migration, so be sure you can roll back any unwanted changes quickly.

How long will the migration take? What are the coexistence requirements?

With a detailed inventory and analysis of what's in scope, you can begin to estimate how long the migration will take. Analyze and document how users will need to work, collaborate and communicate while the migration is going on, when some of them have been moved to Office 365 but others are still using the legacy environment. (Because this period is so important, the next best practice is devoted to exploring planning for coexistence in detail.)

When can the source environments be decommissioned?

Depending on your goals, you might be able to decommission some or all of your source environments after the migration. For example, if you're moving entirely to Exchange Online, you'll want to retire your on-premises Exchange as soon as possible after the migration to eliminate the effort and cost of maintaining it. Think through how you'll verify that the new environment is working properly and how long you should wait to be confident that the source environment is no longer needed.

Do plan for coexistence

The success of a migration is measured primarily by the experience of the users affected by it, so you want your user experience to be as seamless as possible. Migrations can take months to complete; if users are unable to do their work, collaborate effectively, or communicate both internally and externally, the business will suffer — and you and your team will take the heat.

Migrations can take months to complete; you need to ensure users can work, collaborate and communicate throughout the process.

Let's consider an email migration from on-prem Exchange to Exchange Online. During the preparation phase, you will have archived old email and perhaps identified sensitive mailboxes that shouldn't move to the cloud. But you'll likely still have a lot of large mailboxes left, and getting them all moved them will take time. To ensure that users can still work effectively, you'll want to sync the source and target mailboxes behind the scenes, along with calendars, address lists and public folders. Even when some users have been migrated and others have not, they'll all still be able to communicate, schedule meetings, collaborate and so forth. When it's time to migrate a particular group of users, you simply flip a switch that points them to their target mailboxes. If there are problems during the migration, you can just switch the users back to their source mailboxes.

Similarly, you'll want to be able to sync your AD users and groups so you can migrate them seamlessly in groups, taking into account users' schedules and departmental requirements. And you need to seamlessly migrate your back-end resources, such as file servers, databases and SharePoint sites, since users depend on them for business-critical processes.

However, with native tools, none of this will be easy. To synchronize data, you'd have to create extensive scripts and schedule them to run repeatedly to keep things up to date. And dealing with issues will be an ordeal; for example, reverting a mailbox migration will be a long process that requires moving the mailboxes back to the source environment. So look for third-party tools that offer strong coexistence capabilities.

With native tools, reverting a mailbox migration is a long process that requires moving the mailboxes back to the source environment, so look for third-party tools that offer strong coexistence capabilities.

Do minimize the impact on the business

Planning for coexistence is one of the most important ways to minimize the impact of a migration on the business, but there are several other factors to consider as well.

Accuracy and Completeness

To be considered successful, a migration has to be complete and accurate. It's not enough to ensure that all the required data has been moved; users need to be able to work effectively in the new environment. For example, you want to make sure to update each user's Windows and Outlook profiles so that after they are migrated, they see no difference in their desktop when they log on, and they connect to the target mailbox environment without having to reconfigure Outlook manually. Similarly, users won't be happy if their SharePoint sites and OneDrive data are not migrated completely and accurately.

Users won't consider the migration a success if they have to reconfigure Outlook manually or their SharePoint data was not migrated completely and accurately.

Performance and Scalability

Another way to make users — and yourself — happy is to complete the migration as quickly as possible. Consider investing in a solution that can perform migration jobs in parallel, and enables you to schedule the jobs

to run when it's most convenient for users, without someone from the IT team having to drive the migration job interactively.

Administration and Reporting

To keep management happy, you need to be able to provide regular updates on the progress of the migration. Efficient management and reporting will also reduce costs and help you complete the migration on time. Native tools don't make it easy to see the current state of the migration; administration often requires creating and running a large collection of custom scripts. Third-party solutions often offer a dashboard that makes it easy to track and report on migration status.

Professional Services

Most IT pros don't perform migrations very often; many members of your team might never have done one at all. And they already have their plates full with other responsibilities. Consider getting help from migration experts, either for the complete project or just for specific pieces.


Migrations jobs often run after normal hours, but any issues that arise need to be addressed as quickly as possible to minimize the impact on the business. Therefore, it's important to have 24/7 support from either your internal team or your professional services partner.

Do implement the ABCs of security

At a minimum, you need to ensure that permissions are not weakened as a result of the migration. But since you're building a new target environment, it's often the perfect time to put in security measures you've always wanted to but found too hard to do in your legacy environments — including these critical ABCs of security.

A move to Office 365 is the perfect opportunity to implement the security measures you've always wanted but found too hard to do in your legacy environment.

Is for audit

To keep your new Office 365 environment secure, you need to audit what's going on there. Microsoft offers some native auditing, and there are some third-party tools that can aggregate that data into whatever auditing platform you prefer.

Having insight into what your users are doing will also help you ensure that that platform is working right and you're getting the full value out of your investment.

Is for backup

You also need to back up your new environment. Microsoft is responsible for keeping the platform running all the time, so if it fails on the back end, they

will bring it back up. But your data is another matter — if you make a mistake and delete something inadvertently, you need to make sure you can recover it yourself. Azure AD does offer a Recycle Bin, but it has important limitations; you need to invest in a comprehensive backup and recovery solution.

To learn more about how the native cloud disaster recovery capabilities of Azure AD differ from those in an on-premises AD environment and what functionality you need in order to properly protect your new cloud or hybrid environment, read our white paper, "Active Directory Recovery in a Cloud or Hybrid World."

Is for control

Security also requires rigorous permissions management and user provisioning (and deprovisioning). You need to carefully manage your AD users and groups as well as SharePoint content permissions and groups, and ensure that all access rights are granted in accordance with the least-privilege principle. With native tools, exercising proper control is difficult, time-consuming and prone to errors, so consider investing in an enterprise identify and access management solution that will automate and streamline the job.

Don't forget about postmigration management

Post-migration management? You might be thinking, "Wait! Isn't one of the key benefits of migrating to Office 365 environment that there's no need for any of that anymore?"

Even though Microsoft will be responsible for performance and availability, you'll still need to manage and secure your Office 365 environment.

It's true that moving to the Microsoft cloud eliminates a lot of administrative responsibilities. Your IT team won't have to manage or provision hardware, for one thing. And Microsoft will be responsible for ensuring high performance and availability of the platform.

How Quest can help

As we've seen, trying to perform a migration with native tools increases both costs and risk. Native tools offer only limited capabilities, so you won't have some functionality you need, and the capabilities that are there often require lots of manual work and complex scripting. Here are specific Quest® solutions that will simplify and streamline each stage of your migration, from pre-migration preparation to migration and coexistence to post-migration management.

Pre-migration tools

  • Enterprise Reporter Suite provides insight into all critical IT assets in your source Windows environment, including both configuration and access permissions. Plus it makes it easy to remediate any issues you uncover, for a faster migration and cleaner, more secure target environment.
  • Change Auditor enables you to easily review configurations, permissions and user activity in your source environment to help ensure a complete inventory and analysis.

But you and your team are still on the hook for plenty. In addition to the security and backup tasks we already discussed, there's the day-to-day administration of Office 365, Azure AD, SharePoint Online, Exchange Online and Skype for Business. Then there are the broader responsibilities of maintaining proper IT governance and compliance with both internal policies and external regulations; you need to be able to efficiently perform permissions reporting, privileged account management, compliance auditing, provisioning, backup and recovery, license management, and so on. You'll want to have the right tools in place well before your migration gets underway so you can ensure a secure and effective environment from day one.

Migration and Coexistence Tools

Quest migration tools ensure a ZeroIMPACT migration with seamless coexistence, thanks to advanced automation, easy management and reporting, and scalability.

  • Migration Manager for Active Directory handles directory migration, including users, groups, computers, volumes, printers, contacts, organizational units, network topology (sites, subnets, site links), and directory permissions.
  • Migration Manger for Exchange migrates and synchronizes mailboxes, distribution groups, calendars and public folders.
  • On Demand Migration safely migrates directories, mailboxes and shared data from one Office 365 tenant to another, all from a single SaaS interface.
  • Migration Manager for PSTs automates the identification, migration and elimination of PST files.
  • Migrator for Notes to SharePoint makes it easy to migrate your IBM Lotus Notes, QuickPlace/Quickr and Domino.Doc applications to Office 365 with high data fidelity and minimal downtime.
  • Migrator for GroupWise ensures an accurate migration from GroupWise to Office 365, moving email, calendars, tasks, personal address books, frequent contacts, archives, recurring meetings and more.
  • Metalogix® Essentials for Office 365 makes it easy to make it easy to consolidate content from SharePoint, Box, Dropbox, Google Drive, personal drives and file shares into Office 365. You can see what was moved successfully and fix issues right from the reporting views.
  • Metalogix Expert delivers insights to help you plan your SharePoint migration, optimize your storage structure and protect against security risks.
  • Metalogix Content Matrix simplifies complex SharePoint migrations and consolidates file shares without disrupting your business processes.

Post-Migration Management Tools

  • One Identity Active Roles delivers comprehensive privileged account management for both Active Directory and Azure AD. It features a single console, unified workflows and a consistent administrative experience across your entire hybrid environment.
  • Change Auditor for Exchange audits, reports and alerts on Exchange and Exchange Online configuration and permissions changes in real time. You can easily search and correlate activity across your hybrid messaging environment, and even prevent anyone but the owner from accessing a sensitive mailbox.
  • Change Auditor for Active Directory simplifies auditing by providing a single, correlated view of activity across your Azure AD or hybrid environment, along with real-time alerts on critical changes. You can also protect your most critical Active Directory objects from being changed.
  • Enterprise Reporter Suite is as useful post-migration as it is during pre-migration planning, providing the insight, reporting and remediation you need to ensure security, compliance and productivity.
  • Recovery Manager for Exchange speeds email discovery by enabling you to search multiple email sources simultaneously from a single interface, including Office 365 mailboxes, on-prem mailboxes and PSTs. Since there's no backup for the mailboxes in Office 365, it can't recover them, but it can read the content in them and restore it to a PST to help your legal teams extract the data.
  • On Demand Recovery for Azure Active Directory enables fast, secure recovery of Azure AD users, attributes, groups and group membership from a single SaaS interface.
  • Unified Communications Command Suite enables you to analyze costs, adoption and performance across Office 365, Exchange, Skype for Business and Cisco Unified Communications Manager, so you can improve both security and quality of experience.
  • Metalogix StoragePoint helps you optimize storage to control SharePoint costs and ensure strong performance.
  • Metalogix ControlPoint helps you secure, administer and govern the sensitive content in your SharePoint environment by spotting suspicious user activity, identifying documents that contain personal and sensitive information, and more.
  • Metalogix Sensitive Content Manager detects and classifies sensitive SharePoint content on premises and in the cloud.
  • Metalogix Archive Manager automatically archives, manages and secures all of your organization's files and emails.

Award-Winning Services and Support

Of course, migrations are still complex undertakings, and most IT pros have relatively little experience with them. Our award-winning, 24x7 technical support is ready to help you troubleshoot any issues that might arise during the migration. If you want further assistance, look no further than our Professional Services team. With hundreds of migrations under their belt, they can help you reach your migration goals, whether you need expert advice, full project management or something in between.


Migrations are both complex and critical, and Office 365 migrations are no exception. The good news is, the path is well trodden. Following the practices laid out here and choosing the right migration tools will help you ensure a faster and more accurate migration that minimizes the impact on your users and the business.

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About Quest

At Quest, our purpose is to solve complex problems with simple solutions. We accomplish this with a philosophy focused on great products, great service and an overall goal of being simple to do business with. Our vision is to deliver technology that eliminates the need to choose between efficiency and effectiveness, which means you and your organization can spend less time on IT administration and more time on business innovation.