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Five Key Steps for a Successful Office 365 Migration

By Nathan Zych, Chief Executive Officer · · Updated July 10, 2025 · 5 min read

Five Key Steps for a Successful Office 365 Migration

Five Key Steps for a Successful Office 365 Migration


Migrating to Office 365 from other platforms is a relatively easy process. Office 365 is a cloud-based solution; therefore, it is incredibly simple to deploy across multiple computers. The downside is that it can take a tremendous amount of time, and may even result in extended downtime if unforeseen issues arise.

To help business organizations considering migrating to Office 365, we’ve put together a list of 5 key steps they can follow for a faster and stress-free migration.

1. Determine Which Systems are Affected by the Migration

Depending on the needs of the organization, complete migration is not always necessary. The company may choose to migrate email, documents, or shared files. In some cases, businesses may only want to migrate mailboxes to the Exchange Online system.

Determining which systems and files are affected is the first step in the migration process. Taking this step enables staff to identify applications that may need to be reconfigured as a result of the migration.

For example, a content management system (CMS) may be linked with the current email platform. When migrating email to Exchange Online, administrators may need to edit settings or options in the CMS to accommodate the new system.

IT staff may also need to determine if files being transferred to the cloud are integral to the functioning of other software. Software that depends on these files may need updating.

2. Choose the Right Office 365 Licensing Plan

Microsoft offers Office 365 through a variety of plans designed for small businesses and larger enterprises. After determining which systems are impacted by the migration, businesses can decide which plan meets their specific needs.

There are three primary Office 365 plans available for businesses:

  • Office 365 Business Premium
  • Office 365 Enterprise E3
  • Office 365 Enterprise E5

The Office 365 Business Premium includes the standard Microsoft Office applications such as Outlook, Word, Excel, PowerPoint, and Access, in addition to OneDrive, Microsoft Exchange, SharePoint, and Microsoft Teams.

The Enterprise E3 includes everything in Business Premium while providing access to more advanced enterprise features such as Microsoft Planner and Skype Meeting Broadcast.

The Enterprise E5 includes everything in E3 while adding even more advanced security features such as Advanced Threat Protection and Advanced Data Governance.

When selecting a plan, it is also important to consider the number of licenses that are needed. Each plan includes a monthly fee per user. These plans are also capped at a maximum of 300 users. If additional licenses are required, the business will need to work with a Microsoft expert to set up customized solutions.

3. Conduct an Audit of Existing Systems

After selecting the right plan, it is time to conduct a detailed audit of all existing systems. This step will enable IT administrators to determine how many workstations or users need to be migrated.

During the audit, the IT staff should also clean up data. Old users or accounts that are no longer active should be deleted.

If any existing systems are phased out during the migration, the audit should also determine the best way to transition to the Office 365 products. For example, businesses may need to wait until the end of a contract with a software vendor before replacing licensed software.

When conducting this audit, IT administrators should also begin developing a disaster-readiness plan.

Microsoft has attempted to make migrating to Office 365 less stressful for large organizations and small businesses. Unfortunately, switching to different software does not always go as planned.

Organizations should implement a plan in case the migration is not a smooth process. This disaster-readiness plan typically includes backups of critical systems, mailboxes, and other platforms affected by the migration.

4. Set a Timeframe for the Migration Process

With the previous steps completed, the business can begin setting a timeframe for the migration process.

In order to do that, they will need to estimate the time required to complete the migration. Microsoft provides a detailed breakdown of estimated migration durations based on the type of migration chosen.

With less than 1,000 mailboxes, businesses may complete migration to Exchange Online in just five days. With 10,000 mailboxes, the same process may take up to 30 days.

The existing mailboxes are not inactive during the migration process. Files and documents also remain available from existing storage solutions. However, when the migration is completed, it is time to switch to the new Office 365 applications and services.

Setting a date for this transition ensures that staff is prepared. It also gives organizations time to implement a communication plan.

5. Develop a Communication Plan to Inform Users

After setting a timeframe, organizations must ensure that everyone affected by the migration is prepared for the process. This includes clients and employees.

Many organizations refer to this part of the planning stage as the communication plan. It provides a way to inform users about impending changes that may impact the way that they use specific services or software.

For example, when migrating mailboxes to Exchange Online, individuals may need to learn the basic steps needed to access their new mailboxes. Some organizations opt to use training programs to orient their employees.

Final Thoughts

Office 365 migrations can be easy or complex, depending on the number of users, applications, and platforms that are impacted.

We’ve provided a number of key steps to help avoid unforeseen issues, and allow for a fast smooth transition.

While these migrations are relatively straightforward, every business has different needs. If the complexities of the organization are too much for the internal staff to handle, working with a Microsoft partner like Outsource IT is a great alternative.

As a Microsoft Gold partner, we are experts when it comes to Office 365 migration. We can handle the entire process from start to finish, or offer timely assistance during the planning and implementation stages. Contact an Outsource IT account manager for more information.

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About the author

Nathan Zych, Chief Executive Officer

Written and reviewed by the Outsource IT team, a Burlington, Ontario managed IT services provider supporting businesses across the GTA for over 20 years. Meet the team.

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