How I Plan and Execute SharePoint Migrations to Microsoft 365 (Real-World Approach)

TL;DR

A successful SharePoint migration is never just about moving files. It requires planning, governance, and a deliberate effort to minimize disruption. This guide outlines a real-world approach based on practical experience across multiple migration projects.

When you skip the planning phase, you carry old problems into a new platform. Broken permissions, outdated content, poor adoption, and security risks do not fix themselves after go-live. The key is to treat migration as a strategic project, not just a technical one.

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Table of Contents

1. Why SharePoint migrations fail
2. My migration approach
3. Step 1: Discovery and assessment
4. Step 2: Content audit and cleanup
5. Step 3: Information architecture
6. Step 4: Permissions strategy
7. Step 5: Migration execution
8. Real-world challenges
9. Governance strategy
10. Post-migration optimization
11. Final thoughts

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1. Why SharePoint Migrations Fail

Most SharePoint migrations do not fail because of technical limitations. They fail because of poor planning and unrealistic expectations.

Here are the most common reasons I have seen migrations go wrong:

• Broken permissions: Migrating without auditing permissions leads to access issues, oversharing, and security risks in the new environment.
• Migrating outdated content: Teams move everything, including files that have not been touched in years, making the new environment just as cluttered as the old one.
• Poor user adoption: Users are not prepared for the change, so they resist using the new platform or revert to old habits like saving files locally.
• Security risks: Without a permissions review, sensitive data can end up exposed to users who should not have access.

The single biggest issue behind all of these is lack of planning. When organizations treat migration as a weekend task instead of a structured project, they end up paying for it in cleanup, rework, and frustrated users.

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2. My Migration Approach

Over multiple migration projects, I have developed a repeatable approach that keeps things structured without being overly rigid. It breaks down into five core steps:

1. Discovery and assessment
2. Content audit and cleanup
3. Information architecture
4. Permissions strategy
5. Migration execution

Each step builds on the previous one. Skipping steps or doing them out of order usually leads to problems later.

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Step 1: Discovery and Assessment

Before you can plan anything, you need to understand what you are working with.

What to analyze

• Current environment: How many site collections, subsites, lists, and libraries exist? What is the total size? Where is the content stored?
• Customizations: Are there custom solutions, web parts, event receivers, or timer jobs? These will not migrate automatically and need to be evaluated for replacement.
• Risks: Identify large lists, complex permission structures, legacy workflows, and anything that could cause issues during migration.

Tools I use

• SharePoint Migration Assessment Tool (SMAT): Provided by Microsoft, useful for identifying potential migration blockers.
• PowerShell scripts: Custom scripts for inventorying site collections, subsites, lists, libraries, permissions, and content types. My open-source SharePoint Migration Scoping Toolkit is designed specifically for this.
• ShareGate: Commercial tool with strong reporting capabilities for both assessment and migration execution.

The goal of discovery is not to create a perfect inventory. It is to understand the scope well enough to make informed decisions about what to migrate, what to archive, and what to leave behind.

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Step 2: Content Audit and Cleanup

This is the step most teams skip, and it is the one that makes the biggest difference.

Why cleanup matters

Migrating everything means you are paying to move, store, and manage content that no one uses. It also means users have to wade through irrelevant files in the new environment.

What to clean up

• Remove outdated content: Files that have not been modified or accessed in years are candidates for deletion or archival.
• Archive unnecessary data: Content that has regulatory or legal retention requirements but is not actively used should be moved to an archive rather than migrated to the active environment.
• Reduce migration scope: Every file you remove from scope reduces migration time, cost, and risk.

How I approach it

1. Generate reports on last modified dates, file sizes, and access patterns.
2. Share the reports with site owners and ask them to flag content for deletion, archival, or migration.
3. Set a deadline. If site owners do not respond, apply a default policy (usually archive).

This step alone can reduce migration scope by 30 to 50 percent in many organizations.

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Step 3: Information Architecture

Migration is an opportunity to redesign how content is organized. Do not just replicate the old folder structure in the new environment.

Key principles

• Flat structure over deep nesting: SharePoint Online works best with shallow hierarchies. Avoid deeply nested folders and subsites.
• Use modern SharePoint features: Hub sites, metadata navigation, content types, and managed metadata make it easier to find and manage content compared to folders alone.
• Plan for scalability: Think about how the structure will work as the organization grows. A design that works for 10 sites may not work for 100.

What to design

• Hub site architecture: Group related sites under hub sites for shared navigation, search, and branding.
• Site provisioning model: Define templates and naming conventions for new sites so the environment stays organized over time.
• Metadata strategy: Use content types and managed metadata for classification instead of relying entirely on folder structures.

The information architecture does not need to be perfect at launch. It needs to be good enough to support the initial migration and flexible enough to evolve.

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Step 4: Permissions Strategy

Permissions are one of the most common sources of post-migration issues. If you do not address them before migration, you will be dealing with access problems for months.

What to audit

• Unique permissions: Identify items, folders, lists, and sites with broken inheritance. These are the most common source of permission-related issues.
• Direct user permissions: Look for cases where individual users have been granted access directly instead of through groups.
• Stale accounts: Remove permissions for users who have left the organization or changed roles.

How to fix it

• Align access with roles: Use security groups or Microsoft 365 groups to manage access. Map permissions to job roles rather than individual users.
• Simplify inheritance: Reduce the number of items with unique permissions. In most cases, inheriting permissions from the parent site or library is sufficient.
• Document the model: Create a permissions matrix that maps roles to sites and libraries so it is clear who has access to what.

Tools that help

• PowerShell scripts to export and analyze permission structures.
• ShareGate for permission reporting and remediation.
• Microsoft 365 access reviews for ongoing governance.

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Step 5: Migration Execution

Once discovery, cleanup, architecture, and permissions are in place, the actual migration is the straightforward part.

Tools I use

• SharePoint Migration Tool (SPMT): Free tool from Microsoft for migrating from file shares and SharePoint Server to SharePoint Online.
• ShareGate: Commercial tool with support for incremental migration, scheduling, and detailed logging.
• PowerShell and the SharePoint Online Management Shell: For scripting bulk operations and automating repetitive tasks.

Migration strategy

• Migrate in phases: Start with a pilot group, validate the results, then expand to additional teams. Avoid big-bang migrations where everything moves at once.
• Use incremental migration: Most tools support delta or incremental migration, which only moves new or changed content. This reduces downtime and risk.
• Validate continuously: After each phase, verify that content, permissions, and metadata migrated correctly. Do not wait until the end to check.

Common pitfalls

• Filename and path length limits: SharePoint Online has a 400-character path limit. Identify and fix long paths before migration.
• Special characters: Some characters that are valid in on-premises file systems are not supported in SharePoint Online.
• Version history: Decide in advance how many versions to migrate. Migrating full version history can significantly increase migration time and storage.

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6. Real-World Challenges

Even with good planning, every migration has unexpected challenges. Here are the ones I encounter most often:

Legacy workflows breaking

SharePoint 2010 and 2013 workflows do not migrate to SharePoint Online. They need to be rebuilt in Power Automate or retired. This is often the most time-consuming part of a migration project because it requires understanding the business logic behind each workflow.

Complex permissions

Organizations that have been running SharePoint for years often have deeply nested, inconsistent permission structures. Cleaning these up before migration is essential, but it takes time and requires buy-in from site owners.

User resistance to change

Even when the new environment is objectively better, users resist change. They are comfortable with the old system and do not want to learn something new. This is why communication, training, and change management are just as important as the technical migration.

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7. Governance Strategy

Migration without governance is just moving chaos from one place to another.

Define ownership

Every site should have a clear owner who is responsible for its content, permissions, and lifecycle. If no one owns it, it will not be maintained.

Set policies

• Retention policies: Define how long content should be kept and what happens when it expires.
• Access policies: Establish rules for who can create sites, share content externally, and manage permissions.
• Naming conventions: Standardize site names, group names, and document library names so the environment stays organized.

Plan long-term maintenance

Governance is not a one-time activity. Build regular reviews into your process:

• Quarterly access reviews to verify permissions are still appropriate.
• Annual content audits to identify and clean up stale content.
• Ongoing monitoring using tools like Microsoft Purview and SharePoint admin reports.

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8. Post-Migration Optimization

The work does not stop when migration is complete. The first few weeks after go-live are critical.

Clean up the environment

• Remove temporary migration accounts and permissions.
• Delete source content once validation is complete (or archive it with a clear retention date).
• Update documentation and links that reference the old environment.

Improve performance

• Review search configuration to make sure content is being indexed and surfaced correctly.
• Optimize large libraries with indexed columns, views, and metadata navigation.
• Monitor storage usage and address any unexpected growth.

Train users

• Provide targeted training for common tasks like uploading files, sharing content, and finding documents.
• Create quick reference guides for new features like co-authoring, version history, and metadata search.
• Designate champions in each team who can help their colleagues with the transition.

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9. Final Thoughts

SharePoint migration is not just a technical project. It is a strategic opportunity to improve how your organization manages content, collaboration, and governance.

The organizations that get the most value from migration are the ones that treat it as a chance to clean up, redesign, and set up for the future, rather than just copying files from one system to another.

If you approach it with a clear plan, the right tools, and a focus on people as much as technology, the migration will go smoothly and the new environment will actually be an improvement.

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FAQ

How long does a typical SharePoint migration take?

It depends on the size and complexity of the environment. A small organization with a few hundred gigabytes can often complete a migration in a few weeks. Large enterprises with terabytes of data and complex customizations may take several months.

Should I migrate everything or start fresh?

In most cases, a hybrid approach works best. Migrate active content that people use regularly, archive content that needs to be retained but is not actively used, and delete content that is no longer needed.

What is the best migration tool?

There is no single best tool. SPMT is a solid free option for straightforward migrations. ShareGate and other commercial tools offer more features for complex environments. The best tool depends on your specific requirements and budget.

Do I need to rebuild all my workflows?

SharePoint 2010 and 2013 workflows will not work in SharePoint Online. You need to evaluate each workflow and decide whether to rebuild it in Power Automate, replace it with a different solution, or retire it entirely.

How do I get users to adopt the new environment?

Start communicating early, involve key users in the pilot phase, provide training, and make the new environment genuinely better than the old one. If users see value in the change, adoption follows.

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If you have questions about SharePoint migration or need guidance on planning your next project, feel free to reach out.