SharePoint to SharePoint Online Migration
Enterprise guide to migration tools, assessment, content audit, site mapping, incremental migration, cutover planning, and post-migration validation.
Why Migrate from SharePoint Server to SharePoint Online Now
How do you migrate from SharePoint Server to SharePoint Online? Enterprise SharePoint migration follows a 6-phase methodology: Assessment (inventory sites, customizations, and workflows), Content Audit (identify and remove ROT content — typically 30-50% reduction), Site Mapping (design target information architecture), Pilot Migration (validate tools and benchmark throughput), Incremental Migration (bulk copy with delta syncs to minimize downtime), and Cutover with Validation (final sync, URL redirect, and comprehensive testing). Tools: SPMT for small migrations, ShareGate for most enterprise migrations, Metalogix for complex environments. EPC Group has migrated 500+ SharePoint environments with 99.9% content integrity and minimal user downtime.
The clock is running out for on-premises SharePoint. SharePoint Server 2016 and 2019 extended support both end in July 2026. After that date, Microsoft provides no security patches, no bug fixes, and no support. Running unsupported SharePoint is a compliance violation for any regulated industry — HIPAA, SOC 2, PCI DSS, and FedRAMP all require supported software with current security patches.
Beyond compliance, the feature gap between SharePoint Server and SharePoint Online grows every month. SharePoint Online now includes Copilot integration, SharePoint Premium (formerly Syntex) for document intelligence, Loop components for collaborative content, and modern web parts that are years ahead of on-premises capabilities. Organizations staying on-premises are falling behind in productivity and collaboration.
EPC Group has executed 500+ SharePoint migrations from versions 2007, 2010, 2013, 2016, and 2019 to SharePoint Online. This guide shares our complete enterprise migration methodology.
Migration Tools Comparison
Choosing the right migration tool depends on data volume, customization complexity, budget, and migration timeline requirements.
| Feature | SPMT (Free) | ShareGate | Metalogix (Quest) |
|---|---|---|---|
| Cost | Free | $10K-25K/year | $15K-40K+ |
| Source Versions | 2013, 2016, 2019 | 2007, 2010, 2013, 2016, 2019, SE | 2007, 2010, 2013, 2016, 2019, SE |
| Incremental Migration | Yes | Yes (excellent) | Yes |
| Pre-Migration Reports | Basic | Comprehensive | Comprehensive |
| Content Mapping | Basic (CSV) | Advanced (GUI + CSV) | Advanced (GUI) |
| Scheduling | Limited | Full scheduling | Full scheduling |
| Metadata Preservation | Good | Excellent | Excellent |
| Permission Migration | Basic | Full (with mapping) | Full (with mapping) |
| Workflow Migration | No | No (provides inventory) | Partial (Nintex only) |
| Throughput | Moderate | High (parallel streams) | High (parallel streams) |
| Best For | Small/medium, budget | Most enterprise migrations | Complex, highly customized |
EPC Group recommends ShareGate for 80% of enterprise migrations. It provides the best balance of capability, usability, and cost. SPMT is appropriate for smaller migrations or when budget is extremely constrained. Metalogix excels in environments with heavy Nintex workflow usage or complex content mapping requirements.
Phase 1: Assessment and Discovery
Assessment is the foundation of a successful migration. Skip this phase and you will discover migration blockers mid-project — costing weeks of rework and blown timelines. A thorough assessment takes 1-2 weeks and prevents months of downstream problems.
Site Collection Inventory
Document every site collection: URL, template type, owner, size, last modified date, number of sites and subsites, and content database. Generate a complete map of the source environment. For SharePoint 2013/2016/2019, use PowerShell with Get-SPSite and Get-SPWeb cmdlets. For older versions, use STSADM or third-party scanning tools. Typical enterprise environments have 50-500 site collections with 500-5,000 sites.
Customization Audit
Identify all customizations that will need special handling: farm solutions (WSP packages), sandboxed solutions, custom master pages, custom page layouts, SharePoint Designer workflows, InfoPath forms, custom web parts, BCS connections, and custom content types. Each customization must be categorized: migrate as-is (if supported), rebuild for SharePoint Online (SPFx, Power Automate, Power Apps), or retire (if no longer needed).
Content Analysis
Analyze content by: total size, file count, file types (identify unsupported types like .exe), large files (over 250 GB — SharePoint Online file size limit is 250 GB), long file paths (URL limit is 400 characters), special characters in file names that are not supported in SharePoint Online, and version history depth. Content analysis informs cleanup priorities and migration scheduling.
User and Permission Mapping
Map source Active Directory accounts to Azure AD accounts in the target tenant. Identify: accounts that exist in both AD and Azure AD (direct mapping), accounts only in AD (need Azure AD creation or hybrid sync), external accounts (need guest invitation in Azure AD), and service accounts used for automated processes (need Azure AD app registrations or managed identities). Permission mapping is the most tedious but most critical assessment task.
Phase 2: Content Audit and Cleanup
The single most impactful thing you can do before migration is clean up content. Every organization has decades of accumulated ROT (Redundant, Obsolete, Trivial) content. Migrating ROT wastes time, money, and creates a messy target environment. Clean it up before migration — not after.
Redundant Content
Typical: 15-25% of total content
- Duplicate files across multiple sites
- Multiple versions of the same document in different locations
- Copied team sites from old projects
- Exported reports that exist in the source system
Obsolete Content
Typical: 20-35% of total content
- Documents not accessed in 3+ years
- Content from departed employees
- Old project sites with no active stakeholders
- Superseded policies and procedures
- Archived sites that were never actually archived
Trivial Content
Typical: 5-15% of total content
- Temporary files and drafts
- Meeting notes for meetings held years ago
- Test sites and sandbox content
- Placeholder documents with no real content
- Screenshots and one-off images
EPC Group content audits use automated scanning tools that categorize every file by freshness, owner status, duplication, and usage patterns. Business owners receive a categorized report and make disposition decisions. Typical result: 30-50% content reduction, which directly reduces migration duration, cost, and SharePoint Online storage consumption.
Phase 3: Site Mapping and Information Architecture
Migration is an opportunity to fix the information architecture mistakes of the past. Most on-premises SharePoint environments evolved organically over 10-15 years, resulting in: deeply nested subsite hierarchies (5+ levels deep), inconsistent navigation, duplicate sites for the same purpose, and no hub site structure. Redesign the architecture for SharePoint Online before migrating content into it.
Flatten Subsite Hierarchies
SharePoint Online best practice is flat architecture: hub sites connect related sites through association, not through subsite nesting. Convert deep subsite trees into standalone sites associated with a hub. This improves performance, simplifies permissions, and enables modern site features that are not available on classic subsites.
Hub Site Design
Organize sites into hub site families: departmental hubs (HR Hub, Finance Hub, IT Hub), project portfolio hubs (all active project sites), and topic hubs (Compliance Hub, Training Hub). Hub sites provide: shared navigation across associated sites, cross-site search, consistent branding, and aggregated news and content. Plan 5-15 hub sites for a typical enterprise.
URL Planning
Design clean, consistent URLs for the target environment. Source: https://sharepoint.contoso.com/sites/HR/Benefits/2024/OpenEnrollment. Target: https://contoso.sharepoint.com/sites/HR-Benefits. Shorter URLs are easier to share, bookmark, and remember. Document the complete URL mapping for every source-to-destination site pair. This mapping drives the migration tool configuration.
Metadata and Content Type Strategy
Review and standardize managed metadata term sets before migration. Consolidate duplicate term sets. Plan content type inheritance from the content type hub. Decide which custom content types to migrate versus retire. Ensure column names and types are consistent across sites that will share content types in SharePoint Online.
Phases 4-5: Incremental Migration and Cutover
Incremental migration is the key to minimizing downtime. Instead of a single big-bang migration that requires days of downtime, incremental migration pre-stages content over weeks, leaving only a small delta sync for the cutover window.
Pilot Migration
Migrate 2-3 representative sites first: one simple team site, one complex site with custom content types, and one large document library. Validate: content integrity (file counts, metadata, versions), permission accuracy, migration throughput (GB per hour), and error handling. Use pilot results to estimate the full migration timeline and identify issues before scale.
Wave Planning
Organize sites into migration waves of 10-20 sites each. Wave criteria: department grouping (migrate entire departments together), dependency grouping (sites that link to each other migrate together), complexity grouping (simple sites first, complex sites later). Schedule waves 1-2 weeks apart to allow validation between waves.
Incremental Sync
After initial bulk copy, run daily incremental syncs that migrate only changed content. This ensures the target stays nearly current with the source. On cutover day, the final delta sync processes only changes since the last incremental run — typically completing in minutes for most sites. Configure migration tools to run incremental syncs during off-hours to avoid impacting source server performance.
Cutover Execution
Cutover checklist: 1) Set source sites to read-only, 2) Run final incremental sync, 3) Validate content integrity (automated comparison scripts), 4) Update DNS/URL redirects from old URLs to new URLs, 5) Send user communication with new URLs and training resources, 6) Monitor for 48 hours post-cutover with dedicated support team, 7) Decommission source after 30-day parallel run period.
Phase 6: Post-Migration Validation
Post-migration validation is not optional — it is the difference between a successful migration and a migration that creates more problems than it solves. Validation must be systematic, documented, and involve business users.
| Validation Area | What to Check | Method | Pass Criteria |
|---|---|---|---|
| Content Integrity | File counts, folder structure, metadata | Automated comparison scripts | 100% match (with documented exceptions) |
| Version History | Version count and content per version | Random sample (10% of files) | All sampled files match source versions |
| Permissions | Group membership, permission levels, inheritance | Test with users from each security group | Correct access for all tested roles |
| Metadata | Managed metadata, custom columns, content types | Automated metadata comparison | 100% metadata values match source |
| Search | Content indexed and searchable | Search for known documents | All searched items found within 24 hours |
| Workflows | Rebuilt Power Automate flows function correctly | End-to-end test for each workflow | All workflows complete successfully |
| User Acceptance | Business users can find and use content | Structured UAT with checklist | Stakeholder sign-off per department |
EPC Group post-migration validation includes automated comparison scripts that verify content integrity across every migrated site, plus structured UAT programs with department-specific checklists. We maintain a 30-day parallel run period where both source and target are available, ensuring zero data loss risk. See our complete SharePoint Online vs on-premises decision guide for additional migration planning resources.
Related Resources
SharePoint Consulting Services
Enterprise SharePoint implementation, migration, governance, and managed services from EPC Group.
Read moreSharePoint Online vs On-Premises
Decision framework for evaluating SharePoint Online versus on-premises deployment for your organization.
Read moreSharePoint Migration Services
Enterprise SharePoint migration consulting with proven methodology and 500+ successful migrations.
Read moreFrequently Asked Questions
How do you migrate from SharePoint Server to SharePoint Online?
SharePoint Server to SharePoint Online migration follows a 6-phase process: 1) Assessment — inventory all site collections, content databases, customizations, and workflows. Identify what migrates cleanly, what needs remediation, and what must be rebuilt. 2) Content audit — analyze content freshness, identify ROT (Redundant, Obsolete, Trivial) content for cleanup before migration. 3) Site mapping — design the target SharePoint Online information architecture, mapping source sites to destination sites with URL planning. 4) Pilot migration — migrate 2-3 representative sites to validate the migration tool, identify issues, and benchmark throughput. 5) Incremental migration — migrate content in waves using incremental (delta) sync to minimize cutover downtime. 6) Cutover and validation — final sync, DNS/URL redirect, and comprehensive post-migration testing. EPC Group has migrated 500+ enterprise SharePoint environments, from 2010 through 2019, to SharePoint Online.
What tools are available for SharePoint to SharePoint Online migration?
Three primary migration tools: 1) SharePoint Migration Tool (SPMT) — free Microsoft tool, good for small to medium migrations (under 100 GB), supports file shares and SharePoint 2013/2016/2019. Limited scheduling and reporting. 2) ShareGate (Migrate) — leading third-party tool, excellent for enterprise migrations, supports all SharePoint versions, provides detailed pre-migration reports, incremental migration, and scheduling. $10,000-25,000 annual license. 3) Metalogix (Quest Migration Manager) — enterprise-grade tool with advanced content mapping, workflow migration, and scheduling. Best for complex migrations with heavy customization. $15,000-40,000+. Also: Migration Manager in SharePoint Admin Center (cloud-based, good for file shares), and PowerShell with PnP Provisioning for template-based migrations. EPC Group typically uses ShareGate for 80% of enterprise migrations due to its balance of capability and usability.
How long does a SharePoint to SharePoint Online migration take?
Migration duration depends on data volume, complexity, and migration approach. Small environment (under 100 GB, 10-20 sites): 4-6 weeks. Medium environment (100 GB - 1 TB, 20-100 sites): 8-12 weeks. Large environment (1-10 TB, 100-500 sites): 12-24 weeks. Enterprise environment (10+ TB, 500+ sites): 6-12 months. Key timeline factors: content volume (migration throughput is typically 1-5 TB per week depending on throttling), customization complexity (custom solutions and workflows require rebuilding), content cleanup scope (ROT content removal can add weeks), user training and change management, and business availability windows for cutover. EPC Group accelerates timelines by 30-40% using parallel migration streams and pre-built migration automation scripts.
What cannot be migrated from SharePoint Server to SharePoint Online?
Items that cannot migrate directly and require rebuilding: 1) Server-side code (farm solutions, sandboxed solutions with code, custom timer jobs) — must be replaced with SPFx web parts, Power Automate flows, or Azure Functions. 2) InfoPath forms — must be replaced with Power Apps or SPFx solutions. 3) SharePoint Designer workflows — must be rebuilt in Power Automate. 4) Custom master pages — SharePoint Online uses modern experience; custom branding requires SPFx extensions. 5) BCS (Business Connectivity Services) connections — must be replaced with Power Automate connectors or custom SPFx solutions. 6) Access Services web databases — discontinued, must be migrated to Power Apps + Dataverse. Items that migrate with limitations: managed metadata (term store structure migrates, but term IDs change), content types (migrate but may need re-association), and alerts (do not migrate — users must re-subscribe).
Should we clean up content before or after migration?
Always clean up BEFORE migration. Migrating ROT (Redundant, Obsolete, Trivial) content wastes migration time, storage costs, and creates a messy target environment. Pre-migration cleanup process: 1) Run content analysis reports to identify: files not accessed in 3+ years, duplicate documents, empty sites with no content, versioning bloat (sites with 500+ versions per document), and orphaned content from departed employees. 2) Present findings to business owners for review and disposition decisions. 3) Archive or delete approved content before migration begins. Typical ROT reduction: 30-50% of content is unnecessary and can be archived or deleted. This means a 5 TB migration becomes a 2.5-3.5 TB migration — faster, cheaper, and cleaner. EPC Group content audits use automated scanning tools that categorize content by freshness, owner status, and usage patterns.
Why should we migrate from SharePoint Server now?
Three urgent reasons to migrate in 2026: 1) End of support — SharePoint Server 2016 mainstream support ended in 2021 (extended support ends July 2026). SharePoint 2019 mainstream support ends in 2024 (extended support ends July 2026). Running unsupported software means no security patches, no bug fixes, and audit/compliance risk. 2) Feature gap — SharePoint Online receives monthly feature updates including Copilot integration, SharePoint Premium (Syntex), Loop components, and modern web parts. On-premises versions receive no new features and fall further behind every month. 3) Cost — maintaining on-premises SharePoint farms requires: server hardware (refreshed every 4-5 years), SQL Server licenses, Windows Server licenses, backup infrastructure, disaster recovery infrastructure, and IT staff for patching and maintenance. SharePoint Online eliminates all of these with a per-user subscription model. EPC Group migration ROI analyses typically show 30-50% TCO reduction over 3 years.
What is incremental migration and why does it matter?
Incremental (delta) migration is a technique where the migration tool first copies all content to the destination, then on subsequent runs, only migrates items that have changed since the last run. This is critical for minimizing cutover downtime. Without incremental migration: all content must be migrated in a single pass during the cutover window, which could take days or weeks for large environments. With incremental migration: the initial bulk copy runs over days or weeks while users continue working on the source. On cutover day, only the delta (changes since the last sync) needs to migrate — typically completing in minutes to hours. Example: 5 TB environment, initial bulk copy takes 5 days. Daily incremental syncs take 1-2 hours. On cutover day, the final delta sync takes 30 minutes. Users experience less than 1 hour of downtime versus 5+ days without incremental migration. All three major tools (SPMT, ShareGate, Metalogix) support incremental migration.
How do you handle SharePoint workflows during migration?
SharePoint workflow migration is the most complex aspect of most migrations because workflows cannot migrate directly. Strategy by workflow type: 1) SharePoint 2010 workflows — must be rebuilt in Power Automate. These are the oldest and most common. Document the workflow logic, inputs, outputs, and triggers, then recreate using Power Automate cloud flows. 2) SharePoint 2013 workflows — also must be rebuilt in Power Automate. More complex than 2010 workflows but same migration approach. 3) SharePoint Designer workflows — cannot migrate. Rebuild in Power Automate with equivalent triggers and actions. 4) Nintex workflows — Nintex offers a migration tool (Nintex Automation Cloud) that can convert some on-premises Nintex workflows to cloud workflows, but complex workflows still require manual rebuilding. Best practice: inventory all workflows, categorize by complexity (simple approval, multi-stage, integration-heavy), prioritize by business criticality, and rebuild the most critical workflows first in Power Automate before cutover. EPC Group workflow migration teams typically rebuild 80% of workflows in Power Automate with improved functionality.
What post-migration validation should be performed?
Post-migration validation covers five areas: 1) Content integrity — verify file counts, folder structures, and metadata match between source and destination. Run checksums on a random sample of files. Verify version history migrated correctly. 2) Permission validation — confirm that SharePoint groups, permission levels, and individual permissions match the migration plan. Test access with representative users from each security group. 3) Functionality testing — verify document libraries, lists, views, content types, managed metadata, search, and navigation work correctly in SharePoint Online. 4) Workflow validation — test all rebuilt Power Automate flows with end-to-end scenarios. Verify triggers fire correctly and approvals route to the right people. 5) User acceptance — conduct structured UAT with business users from each department. Provide a checklist of items to verify and a feedback mechanism. Allow 1-2 weeks for UAT before decommissioning the source environment. EPC Group post-migration validation includes 100+ test cases per site collection and automated comparison scripts.
Plan Your SharePoint Migration
EPC Group migration assessments evaluate your on-premises SharePoint environment, identify migration blockers, estimate timeline and cost, and deliver a migration roadmap. With 500+ successful migrations, we know how to get it right the first time.