What is pre-migration assessment?
Also known as
Definition
A pre-migration assessment is how you find out what's actually in your source environment before anything moves. Volume, structure, permissions, dependencies, and what the target needs to look like.
It's a set of decisions: what moves, what gets cleaned up first, what gets archived, and what gets left behind. Without it, timelines are guesses and surprises show up mid-migration.
tip
ShareGate's source analysis gives you an overview of your source environment so you can estimate migration effort and take action on potential issues before anything moves.
Why it matters
The difference between a migration that goes smoothly and one that doesn't is usually what happened before any data moved.
- Migration: Not everything needs to move. Outdated files, inactive sites, and duplicate content create clutter in the target environment if nobody decides what to do with them first. A pre-migration assessment is the moment to make those decisions.
- Governance & security: Outdated or unnecessary data increases risk. Old files may contain sensitive information that becomes accessible to Copilot or other AI tools once the content lands in the new environment.
- Day-to-day operations: Without a pre-migration assessment, scope creep, unexpected complexity, and mid-project blockers are the norm. With one, the project has a realistic scope, a wave plan grounded in what's actually there, and fewer surprises after cutover.
Commonly confused with: Pre-migration inventory
An inventory lists what exists in the source environment. An assessment goes further. It evaluates what should move, what needs remediation, and what the findings mean for migration planning.
What we see out there
Scope is always bigger than expected.
IT teams start an assessment and find more than anticipated. The scope conversation happens after the inventory, not before.
Timelines get set before complexity is understood.
Organizations ask for a migration timeline before anyone has looked at the source environment. The assessment is what makes a realistic timeline possible. Without it, the estimate is a guess.
"Garbage in, garbage out."
Migrating a disorganized environment produces a disorganized destination. An assessment is the moment to decide what's worth moving and what isn't, before the mess gets a new address.
Frequently asked questions
What should be assessed?
Start with what exists: volume and type of content across each workload, site structure, and who owns what. Then look at risk: permissions complexity, broken inheritance, custom functionality that may not work in the target environment, and dependencies between workloads. Finally, make decisions: what moves, what gets archived, what gets cleaned up, and what gets left behind. The more thoroughly the source is understood before migration starts, the fewer surprises during it.
How long does an assessment take?
It depends on the size and complexity of the environment. A small, clean environment can be assessed quickly. A large environment with years of accumulated content, complex permissions, and legacy customizations takes longer. Skipping or shortcutting the assessment is one of the most common reasons migrations go over budget and timeline.
What tools help with assessment?
A source analysis gives you a clear picture of what's in the environment: volume, site counts, permissions complexity, and potential issues. For SharePoint 2016 and 2019 environments, Microsoft's SharePoint Migration Assessment Tool (SMAT) is a starting point, though it doesn't cover all scenarios. A pre-check in ShareGate Migrate simulates the migration and surfaces warnings and errors before the real run.
What risks should be scored during assessment?
Permissions complexity: number of unique permissions, broken inheritance, direct assignments. Content sensitivity: files or sites that need special handling before they move. Custom functionality: workflows, forms, or solutions that may not work in the target environment. Workload dependencies: Teams that depend on Exchange, SharePoint sites connected to Groups. Rate of change: actively used content that needs incremental runs to stay current before cutover.
