SharePoint On-Premises to Cloud: Migration Strategy Guide for IT Leaders

SharePoint on-premises reached end-of-support timelines, but migration to Microsoft 365 isn't just a technical lift-and-shift—it's a strategic transformation that requires careful planning, risk management, and executive buy-in.

Why Migration Urgency is Real

Support and Security Timeline Pressure

Microsoft’s support lifecycle for SharePoint Server versions:

• SharePoint 2013: Mainstream support ended April 2018, Extended support ends April 2023
• SharePoint 2016: Mainstream support ends July 2021, Extended support ends July 2026
• SharePoint 2019: Mainstream support ends July 2024, Extended support ends July 2029

Running unsupported versions exposes organizations to:

• Security vulnerabilities with no patches
• Compliance and audit risks
• Inability to integrate with modern Microsoft 365 features
• Difficulty recruiting talent skilled in legacy platforms

The Business Case Beyond Compliance

At Avantit, we help clients build comprehensive business cases that go beyond “we must migrate”:

Cost Savings:

• Eliminate datacenter costs ($50K-200K annually for mid-sized farms)
• Reduce IT staff time on infrastructure maintenance (1-2 FTEs typically)
• Remove upgrade and patch management overhead

Business Enablement:

• Modern collaboration with Teams integration
• Mobile access and external sharing
• AI-powered search and content discovery
• Integration with Power Platform for automation

Risk Reduction:

• Built-in disaster recovery and business continuity
• Enterprise-grade security and compliance tools
• Automatic updates without downtime

Migration Approaches: Three Paths with Different Trade-offs

Approach 1: Lift-and-Shift (Fastest, Highest Technical Debt)

Timeline: 2-4 months for typical 2TB environment
Best for: Organizations under urgent timeline pressure (support ending soon)

Process:

1. Inventory all sites, libraries, workflows, customizations
2. Use migration tools (ShareGate, SharePoint Migration Tool, AvePoint)
3. Move content “as-is” to SharePoint Online
4. Address broken customizations post-migration

Pros:

• Fastest path to cloud
• Lowest initial cost
• Minimal business disruption

Cons:

• Carries forward all legacy baggage
• InfoPath forms and legacy workflows break
• Custom solutions require rework
• Misses opportunity for modernization

Real Cost: $30K-80K for consulting + tools (100-500 users)

Approach 2: Redesign and Migrate (Balanced)

Timeline: 4-8 months for typical environment
Best for: Most organizations seeking balance between speed and modernization

Process:

1. Audit current state and identify modernization opportunities
2. Redesign site architecture for modern SharePoint patterns
3. Convert InfoPath forms to Power Apps
4. Rebuild workflows in Power Automate
5. Migrate content to new structure
6. Train users on new paradigm

Pros:

• Modernizes while migrating
• Removes legacy technical debt
• Improves user experience
• Sets foundation for future capabilities

Cons:

• Longer timeline
• More change management needed
• Higher initial cost
• Requires careful planning

Real Cost: $80K-200K for consulting + tools (100-500 users)

Approach 3: Transform to Microsoft 365 Ecosystem (Strategic)

Timeline: 6-12 months
Best for: Organizations ready for comprehensive digital workplace transformation

Process:

1. Rethink collaboration strategy (not just SharePoint)
2. Design integrated Microsoft 365 experience (Teams, SharePoint, Power Platform)
3. Migrate content to appropriate modern platforms
4. Implement governance and information architecture
5. Build Center of Excellence for ongoing optimization

Pros:

• Maximizes Microsoft 365 investment
• Creates modern digital workplace
• Enables new ways of working
• Strong governance foundation

Cons:

• Longest timeline
• Significant change management
• Highest consulting investment
• Requires executive sponsorship

Real Cost: $150K-500K for comprehensive program (100-500 users)

The Decision Framework: Choosing Your Path

Assessment Questions for IT Leaders

1. How urgent is your timeline?

• Support ending in < 12 months → Consider Lift-and-Shift or Balanced
• Support ending in 12-24 months → Balanced or Transform
• Support ending in 24+ months → Transform

2. What’s your customization complexity?

• Minimal (mostly out-of-box) → Lift-and-Shift viable
• Moderate (some InfoPath, workflows) → Balanced recommended
• Heavy (custom solutions, integrations) → Transform or Balanced

3. What’s your change capacity?

• Low (IT stretched thin) → Lift-and-Shift, address debt later
• Moderate (can dedicate resources) → Balanced
• High (dedicated transformation team) → Transform

4. What’s your strategic vision?

• Maintain status quo → Lift-and-Shift
• Modernize collaboration → Balanced
• Reinvent digital workplace → Transform

Real Migration Timelines and Resource Requirements

Based on Avantit’s experience with 50+ migrations:

Small Organization (100-250 users, 500GB-2TB)

Lift-and-Shift:

• Timeline: 8-12 weeks
• Internal FTE: 0.5 (IT lead)
• External consulting: 200-300 hours
• Migration tools: ShareGate or SPMT

Balanced:

• Timeline: 16-24 weeks
• Internal FTE: 1.0 (IT lead + power users)
• External consulting: 400-600 hours
• Migration tools: ShareGate + Power Platform licenses

Mid-Size Organization (250-1000 users, 2-10TB)

Lift-and-Shift:

• Timeline: 12-20 weeks
• Internal FTE: 1-2 (IT team + project manager)
• External consulting: 400-800 hours
• Migration tools: Enterprise migration platform

Balanced:

• Timeline: 24-40 weeks
• Internal FTE: 2-3 (IT team + business analysts + change lead)
• External consulting: 800-1500 hours
• Migration tools: Enterprise platform + Power Platform

Enterprise (1000+ users, 10TB+)

Balanced or Transform:

• Timeline: 40-52 weeks
• Internal FTE: 4-6 (dedicated transformation team)
• External consulting: 1500-3000+ hours
• Migration tools: Enterprise platform + full Microsoft 365 stack

Common Migration Risks and Mitigation Strategies

Risk 1: Broken Customizations

Impact: Custom web parts, event receivers, InfoPath forms fail in cloud

Mitigation:

• Inventory all customizations during planning phase
• Classify as: migrate as-is, rebuild modern, retire/replace
• Build SPFx alternatives for critical custom web parts
• Convert InfoPath to Power Apps (plan 40-80 hours per complex form)

Risk 2: Workflow Disruption

Impact: SharePoint 2010/2013 workflows don’t work in SharePoint Online

Mitigation:

• Document all active workflows during inventory
• Prioritize by business criticality
• Rebuild critical workflows in Power Automate (20-60 hours per workflow)
• Accept temporary manual workarounds for low-priority flows

Risk 3: Performance Issues Post-Migration

Impact: Users complain about slow sites, search problems

Mitigation:

• Implement proper site architecture (hub sites, not nested subsites)
• Configure search crawl schedules appropriately
• Optimize large lists/libraries (use metadata, column indexing)
• Set realistic expectations about initial search index build (days to weeks)

Risk 4: User Adoption Failure

Impact: Users continue working around new system, ROI not realized

Mitigation:

• Start change management early (not just training at go-live)
• Identify and train champions in each business unit
• Create role-specific training (not generic)
• Provide ongoing support channel (not just day-one help)

Risk 5: Data Loss or Corruption

Impact: Critical content missing or damaged post-migration

Mitigation:

• Multiple test migrations before production cut-over
• Maintain read-only on-premises environment for 90 days post-migration
• Implement versioning in SharePoint Online before migration
• Have rollback plan for critical workloads

The Avantit Migration Methodology

At Avantit, we follow a proven 6-phase approach:

Phase 1: Discovery & Assessment (2-3 weeks)

• Site inventory and usage analysis
• Customization and integration audit
• User interviews and pain point analysis
• Risk and dependency mapping
• Approach recommendation and cost model

Phase 2: Planning & Design (3-4 weeks)

• Target architecture design
• Migration wave planning (which content when)
• Customization redesign specifications
• Test plan and success criteria definition
• Change management and training strategy

Phase 3: Pilot (4-6 weeks)

• Migrate 2-3 representative sites
• Test all migration patterns
• Validate customization rebuilds
• Conduct user acceptance testing
• Refine approach based on learnings

Phase 4: Wave Migration (8-20 weeks depending on size)

• Execute migration in planned waves
• Monitor and troubleshoot issues
• Provide daily user support
• Track success metrics
• Adjust approach as needed

Phase 5: Hypercare (4-8 weeks post-migration)

• Intensive user support
• Performance tuning and optimization
• Address outstanding issues
• Knowledge transfer to IT team

Phase 6: Optimization & Governance (Ongoing)

• Establish Center of Excellence
• Implement ongoing governance
• Plan next evolution (Teams, Power Platform)
• Measure and report on realized benefits

Cost Considerations: Beyond the Migration Project

Ongoing Microsoft 365 Costs

Licensing:

• Microsoft 365 E3: $36/user/year
• Microsoft 365 E5: $57/user/year
• SharePoint Plan 1: $5/user/month (if not buying full M365)

Change from On-Premises:

• Eliminate: Hardware refresh, datacenter, SQL licensing, backup infrastructure
• Add: Per-user cloud licensing, potential egress costs for heavy API usage

Net Financial Impact: Most organizations see 20-40% cost reduction vs. on-premises total cost of ownership over 5 years.

Unexpected Costs to Budget For

1. Storage overages: Plan for growth, default quotas often insufficient
2. Power Platform licensing: If rebuilding workflows/forms at scale
3. Advanced security features: Some scenarios require E5 or add-on licenses
4. Migration tool licensing: Often charged per user or GB migrated
5. Extended consulting: Complex issues often require more hours than planned

The Bottom Line for IT Leaders

SharePoint migration is inevitable for most organizations, but the “when” and “how” are strategic decisions with multi-year implications.

Good migrations are characterized by:

• Executive understanding and support
• Realistic timelines (don’t rush what can be done properly)
• Balanced investment in technology and change management
• Clear success criteria beyond “content moved”

Failed migrations typically share:

• Treating it as purely technical project
• Underestimating customization complexity
• Skipping pilot phase
• Inadequate user training and support

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Ready to plan your SharePoint migration?

Contact Avantit for a complimentary Migration Readiness Assessment. In a 2-hour workshop, we’ll:

• Review your current SharePoint environment
• Identify migration complexity and risks
• Recommend the right approach for your situation
• Provide high-level timeline and budget estimates
• Answer your specific concerns and questions

Our assessments are honest and consulting-focused—we’ll tell you if you’re not ready to migrate yet and what to do first.