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About EPC Group

EPC Group is a Microsoft consulting firm founded in 1997 (originally Enterprise Project Consulting, renamed EPC Group in 2005). 29 years of enterprise Microsoft consulting experience. EPC Group historically held the distinction of being the oldest continuous Microsoft Gold Partner in North America from 2016 until the program's retirement. Because Microsoft officially deprecated the Gold/Silver tiering framework, EPC Group transitioned to the modern Microsoft Solutions Partner ecosystem and currently holds the core Microsoft Solutions Partner designations.

Headquartered at 4900 Woodway Drive, Suite 830, Houston, TX 77056. Public clients include NASA, FBI, Federal Reserve, Pentagon, United Airlines, PepsiCo, Nike, and Northrop Grumman. 6,500+ SharePoint implementations, 1,500+ Power BI deployments, 500+ Microsoft Fabric implementations, 70+ Fortune 500 organizations served, 11,000+ enterprise engagements, 200+ Microsoft Power BI and Microsoft 365 consultants on staff.

About Errin O'Connor

Errin O'Connor is the Founder, CEO, and Chief AI Architect of EPC Group. Microsoft MVP multiple years, first awarded 2003. 4× Microsoft Press bestselling author of Windows SharePoint Services 3.0 Inside Out (MS Press 2007), Microsoft SharePoint Foundation 2010 Inside Out (MS Press 2011), SharePoint 2013 Field Guide (Sams/Pearson 2014), and Microsoft Power BI Dashboards Step by Step (MS Press 2018).

Original SharePoint Beta Team member (Project Tahoe). Original Power BI Beta Team member (Project Crescent). FedRAMP framework contributor. Worked with U.S. CIO Vivek Kundra on the Obama administration's 25-Point Plan to reform federal IT, and with NASA CIO Chris Kemp as Lead Architect on the NASA Nebula Cloud project. Speaker at Microsoft Ignite, SharePoint Conference, KMWorld, and DATAVERSITY.

© 2026 EPC Group. All rights reserved. Microsoft, SharePoint, Power BI, Azure, Microsoft 365, Microsoft Copilot, Microsoft Fabric, and Microsoft Dynamics 365 are trademarks of the Microsoft group of companies.

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Home/Blog/Office 365 Migration Partner Guide
February 22, 2026•15 min read•Microsoft 365

Office 365 Migration Services: How to Choose the Right Partner in 2026

A decision-maker's guide to evaluating migration partners, avoiding costly mistakes, and ensuring a smooth transition to Microsoft 365.

Quick Answer: The right Office 365 migration partner should hold Microsoft Solutions Partner designation, demonstrate experience at your organization's scale, possess industry-specific compliance expertise, follow a documented methodology with rollback capabilities, and provide post-migration support including user adoption training.

Office 365 Migration Services Choosing Partner | EPC Group - EPC Group enterprise consulting

Office 365 Migration Services Choosing Partner | EPC Group

Enterprise Microsoft consulting insights from EPC Group — 29 years serving Fortune 500.

Why Your Choice of Migration Partner Matters More Than the Technology

Microsoft 365 migration is not primarily a technology challenge. The tools exist, the processes are well-documented, and Microsoft provides extensive native migration capabilities. The real challenge is organizational: managing complexity at scale, maintaining business continuity during transition, and ensuring that the post-migration environment actually delivers the productivity gains that justified the investment.

Organizations that treat migration as a purely technical exercise consistently report higher failure rates, longer timelines, and greater cost overruns. A qualified migration partner brings not just technical execution capability but strategic planning, risk management, and change management expertise that determines whether your migration succeeds or becomes a cautionary tale.

The Seven Critical Evaluation Criteria

1. Microsoft Partnership Status and Certifications

Microsoft's partner program has evolved significantly. The legacy Gold and Silver competency system was replaced by the Microsoft Solutions Partner designations in 2022. Look for partners with Solutions Partner for Modern Work, which specifically validates expertise in Microsoft 365 deployment and migration.

Beyond the partnership designation, evaluate the individual certifications held by the team members who will actually work on your project. Key certifications include Microsoft 365 Certified: Enterprise Administrator Expert, Microsoft Certified: Azure Solutions Architect Expert (critical for hybrid scenarios), and Microsoft Certified: Security, Compliance, and Identity Fundamentals for regulated industries.

2. Scale-Appropriate Experience

A partner that has successfully migrated 50-user companies is not necessarily qualified to migrate a 10,000-user enterprise. The challenges are fundamentally different. At enterprise scale, you encounter issues that simply do not exist in smaller environments:

  • Bandwidth saturation during large data transfers requiring throttling strategies and off-hours scheduling
  • Mailbox size distribution where a small percentage of power users with 50GB+ mailboxes can bottleneck the entire migration
  • Custom application dependencies including SharePoint workflows, InfoPath forms, and legacy Access databases that require remediation
  • Multi-forest Active Directory environments requiring complex identity mapping and synchronization
  • Regulatory holds and eDiscovery requirements that must be maintained throughout the migration process

Ask potential partners for case studies at your specific scale and complexity level. Request references you can contact directly.

3. Industry-Specific Compliance Expertise

If your organization operates in healthcare, financial services, government, or education, compliance is not optional. Your migration partner must understand the regulatory frameworks that govern your data:

IndustryKey RegulationsMigration Impact
HealthcareHIPAA, HITECHPHI must be encrypted in transit, BAA required with Microsoft, audit trails mandatory
Financial ServicesSOC 2, SOX, FINRAData residency requirements, retention policies, communication archiving
GovernmentFedRAMP, ITAR, CJISGCC or GCC High tenant required, cleared personnel for sensitive data
EducationFERPA, COPPAStudent data segregation, parental consent workflows, A1/A3/A5 licensing

4. Documented Methodology with Rollback Procedures

Every credible migration partner should be able to walk you through their methodology before engagement. At minimum, the methodology should include distinct phases for discovery and assessment, architecture design, pilot migration, phased production migration, validation, and hypercare support.

Critically, ask about rollback procedures. What happens if the migration encounters a critical failure? How quickly can they restore services to the pre-migration state? Partners who cannot articulate a clear rollback strategy have not planned for failure, which means they have not planned adequately.

5. Post-Migration Support and User Adoption

The technical migration is typically 40% of the total effort. The remaining 60% is ensuring users actually adopt the new platform effectively. Your partner should provide structured user adoption programs including role-based training, champion networks, and measurable adoption metrics.

Ask specifically about their hypercare period. How many weeks of intensive support do they provide post-migration? What is the escalation path for issues? Do they provide a dedicated support contact or route everything through a general helpdesk?

6. Project Management and Communication

Migration projects fail more often from poor project management than technical issues. Evaluate the partner's project management approach: Do they assign a dedicated project manager? What reporting cadence do they follow? How do they handle scope changes and risk escalation?

Request a sample project plan from a previous engagement (sanitized for confidentiality). This reveals more about their actual methodology than any sales presentation.

7. Pricing Transparency and Contract Structure

Be wary of partners who provide a single fixed price without detailed scope documentation. Enterprise migrations have too many variables for a credible fixed price without thorough assessment. The best partners typically structure engagements as:

  • Phase 1: Paid assessment (2-4 weeks, fixed price) — thorough environment analysis and migration plan
  • Phase 2: Migration execution (priced based on assessment findings) — actual migration work
  • Phase 3: Hypercare and optimization (time and materials or retainer) — post-migration support

Red Flags to Watch For

In 29 years of Microsoft consulting, we have seen partners make promises they cannot deliver. Watch for these warning signs:

  • "Zero downtime guaranteed" — Some downtime or reduced functionality during cutover is normal. Partners who guarantee zero downtime are either using a different definition or setting unrealistic expectations.
  • No pilot phase in the proposal — Skipping the pilot is the single biggest risk factor in migration failures.
  • Junior staff doing the actual work — Confirm that senior engineers, not just project coordinators, will be hands-on during critical migration windows.
  • No mention of data validation — Post-migration data validation is essential. If the partner does not include validation procedures, they are cutting corners.
  • Reluctance to provide references — Any established partner should be able to provide 3-5 references at your organization's scale.

Migration Types and Their Unique Requirements

Exchange to Exchange Online

The most common migration type. Key considerations include hybrid coexistence period, mail flow routing changes, public folder migration strategy, and Exchange to Office 365 migration cutover scheduling. Enterprise environments typically require a hybrid coexistence period of 2-6 months to ensure smooth transition.

Google Workspace to Microsoft 365

Cross-platform migrations are significantly more complex due to feature parity gaps. Google Docs must be converted to Office formats, Google Drive permissions must be mapped to SharePoint/OneDrive, and Google-specific features like Google Forms and Google Sites require alternative solutions.

On-Premises SharePoint to SharePoint Online

SharePoint migrations involve not just content but custom solutions, workflows, InfoPath forms, and site architecture. A partner experienced in SharePoint consulting will assess your custom solutions inventory and develop remediation strategies for components that are not compatible with SharePoint Online.

Tenant-to-Tenant Migration

Required during mergers, acquisitions, and divestitures. These are among the most complex migration scenarios because they involve identity merging, domain transfers, and potential conflicts in configuration and policy. Experience with tenant-to-tenant migration should be a hard requirement for any partner engaged in M&A-related work.

How EPC Group Approaches Office 365 Migrations

With 29 years of Microsoft consulting experience and hundreds of enterprise migrations completed, EPC Group has refined a migration methodology that prioritizes business continuity, compliance, and user adoption:

  • Assessment-first approach — We never provide migration pricing without a thorough environment assessment. This protects both parties from scope surprises.
  • Compliance-native — Our methodology is built for regulated industries. HIPAA, SOC 2, and FedRAMP requirements are baked into our processes, not bolted on.
  • Phased migration with validation gates — Each migration batch is validated before proceeding to the next. No batch proceeds until the previous batch meets all success criteria.
  • Dedicated senior engineers — Your migration is led by engineers with 10+ years of Microsoft platform experience, not rotated through a junior resource pool.
  • 90-day hypercare — Post-migration support extends for 90 days with a dedicated support contact and 4-hour SLA for critical issues.

Frequently Asked Questions

How much do Office 365 migration services cost?

Office 365 migration costs typically range from $15 to $50 per user for straightforward migrations, and $50 to $150+ per user for complex enterprise environments with custom applications, compliance requirements, or hybrid configurations. A 5,000-user organization should budget between $150,000 and $500,000 depending on complexity, including planning, execution, training, and post-migration support. Always request a detailed scope assessment before committing to pricing.

What should you look for in an Office 365 migration partner?

The most important criteria are Microsoft Gold or Solutions Partner designation, documented experience with migrations at your scale (user count and data volume), industry-specific compliance expertise (HIPAA for healthcare, SOC 2 for finance, FedRAMP for government), a proven methodology with rollback procedures, and references from similar organizations. Also verify they provide post-migration support and user adoption training, not just the technical migration.

How long does an Office 365 migration take for a mid-size company?

A typical Office 365 migration for a mid-size company (500-5,000 users) takes 8 to 16 weeks from planning through completion. This includes 2-4 weeks of assessment and planning, 1-2 weeks of pilot migration with a test group, 4-8 weeks of phased production migration, and 2-4 weeks of post-migration optimization. Complex environments with hybrid Exchange, custom SharePoint solutions, or regulatory requirements can extend timelines to 6-9 months.

What are the biggest mistakes companies make during Office 365 migration?

The five most common mistakes are: underestimating bandwidth requirements for large data transfers, failing to inventory and remediate custom applications before migration, skipping the pilot phase and migrating all users simultaneously, not planning for user adoption and training, and neglecting to update DNS records and mail flow rules properly. Each of these can cause extended downtime, data loss, or user productivity drops that far exceed the cost of proper planning.

Can you migrate from Google Workspace to Office 365 without data loss?

Yes, Google Workspace to Office 365 migrations can be completed with zero data loss when executed properly. Microsoft provides native tools like the Google Workspace migration tool in the Exchange admin center, and third-party tools like BitTitan MigrationWiz offer additional capabilities. The key is thorough pre-migration inventory, proper mapping of Google Drive to OneDrive/SharePoint structures, and handling of Google-specific features like Shared Drives, Google Sites, and Google Forms that require manual recreation or alternative solutions in the Microsoft ecosystem.

Planning an Office 365 Migration?

EPC Group has completed hundreds of enterprise Microsoft 365 migrations across healthcare, finance, and government. Start with a structured assessment to understand your environment, timeline, and budget requirements.

Schedule a Migration Assessment
EO

Errin O'Connor

CEO & Chief AI Architect at EPC Group | 29 years Microsoft consulting | Microsoft Press author

← Back to Blog

Office 365 Migration: How to Choose a Partner

Last updated: 2026 · Read time: 9 min

Choosing the right Office 365 migration partner determines whether your migration runs on schedule or creates weeks of disruption. The right partner holds Microsoft Solutions Partner designation, has experience at your scale, knows your industry's compliance requirements, and follows a documented methodology with rollback capabilities. This guide covers every selection criterion.

Key facts

  • Required certifications: Microsoft Solutions Partner designation (formerly Gold Partner).
  • EPC Group: oldest continuous Microsoft Gold Partner in North America (2003–2022). Now a Microsoft Solutions Partner.
  • E3: $36/user/month. E5: $57/user/month (adds Defender, Sentinel, and 6-year audit retention).
  • 5 most common migration failures: bandwidth underestimation, custom app inventory gaps, no pilot phase, no adoption plan, and DNS record errors.
  • EPC Group has completed 11,000+ enterprise Microsoft engagements including Office 365 migrations.

5 criteria for choosing a migration partner

Use these five criteria as your evaluation framework. A competent partner should answer every question without hesitation. Any hesitation is a red flag.

  1. Microsoft Solutions Partner designation — verify at the Microsoft Partner Center. This is the minimum bar for any enterprise migration engagement.
  2. Experience at your scale — ask for references from organizations with your user count and data volume. A firm great at 200-user migrations may struggle at 5,000 users.
  3. Industry-specific compliance expertise — HIPAA for healthcare, SOC 2 for financial services, FedRAMP for government. Ask for the specific controls they configured in a recent engagement.
  4. Documented methodology with rollback — ask to see the runbook. Firms without a documented rollback procedure are not ready to run your migration.
  5. Post-migration support — who handles user adoption, training, and helpdesk escalation in the 30 days after cutover? This is where most budget gets cut and most migrations fail.

How to evaluate technical depth

During partner evaluation, test the team's working knowledge. Ask these questions directly.

  • How do you handle slowly changing dimensions in Power BI data models? (For analytics-heavy migrations.)
  • What is your approach for optimizing DAX measures on large datasets?
  • How do you handle user adoption when migrating from Lotus Notes or Google Workspace?
  • Walk me through your DNS cutover procedure and rollback trigger criteria.
  • What third-party tools do you use for Teams chat history migration?

A competent firm answers these from experience. They describe specific engagements. They do not read from marketing materials.

What a structured migration methodology looks like

Ask to see the migration methodology document before signing a contract. It should include all six components below.

  • Discovery and assessment — stakeholder interviews, mailbox inventory, data source documentation, and custom application inventory.
  • Design phase — documented data models and architecture decisions before any data moves.
  • Iterative development — sprint-based delivery with regular stakeholder reviews. Not a big-bang approach.
  • User acceptance testing — defined success criteria for pilot group sign-off before org-wide cutover.
  • Phased rollout — pilot group first, then departments in waves. Never all-at-once.
  • Post-deployment optimization — usage analytics review, helpdesk ticket triage, and adoption program for 30–60 days post-cutover.

5 most common migration mistakes

These errors appear in a predictable order. Most are avoidable with a good partner.

  1. Underestimating bandwidth — 10+ GB mailboxes across 500+ users saturate most corporate WAN links. Assess network capacity 4 weeks before migration, not the day before.
  2. Custom application gaps — line-of-business apps that integrate with Exchange or SharePoint break silently during migration. Inventory them before you start.
  3. Skipping the pilot phase — migrating all users simultaneously creates an org-wide outage when something goes wrong. Always pilot with 5–10% of users first.
  4. No adoption plan — access to Microsoft 365 does not equal adoption. Training and champion programs are required for measurable productivity gains.
  5. DNS record errors — incorrect MX, SPF, or Autodiscover records break email flow after cutover. Prepare and test DNS changes before migration day.

Licensing: E3 vs. E5

Partner evaluation includes licensing recommendation. A good partner helps you right-size.

  • E3 ($36/user/month) — Microsoft 365 Apps, Exchange Online, SharePoint, Teams, Azure AD P1, and Intune. Covers most mid-market needs.
  • E5 ($57/user/month) adds: Microsoft Defender for Endpoint Plan 2, Microsoft Defender for Cloud Apps, Insider Risk Management, Communication Compliance, Sentinel audit logs, Customer Lockbox, and Audit (Premium) with 6-year retention.

Regulated industries (healthcare, financial services, government) almost always need E5. The cost delta ($21/user/month) is often offset by replacing standalone security tools.

Frequently asked questions

What certifications should a Microsoft 365 migration partner have?

Microsoft Solutions Partner designation is the baseline requirement. Modern Work and Security specializations indicate depth for migration and compliance work. Verify status directly at Microsoft's partner locator, not from the firm's marketing materials.

How much does Office 365 migration consulting cost?

Small organization migrations (under 200 users): $15,000–$40,000. Mid-size migrations (200–1,000 users): $40,000–$150,000. Enterprise migrations (1,000+ users, complex compliance): $150,000–$500,000+. Pricing varies by data volume, compliance scope, and custom application count.

How long should a migration take?

Under 200 users: 4–6 weeks. 200–1,000 users: 8–12 weeks. Over 1,000 users: 12–24 weeks. Any partner promising faster timelines without a pilot phase is cutting the wrong corners.

Can we migrate from Google Workspace to Microsoft 365?

Yes. The migration maps Gmail to Exchange Online, Google Drive to OneDrive/SharePoint, and Google Meet to Teams. Third-party tools (MigrationWiz, BitTitan) handle data transfer. Plan 3–4 weeks of parallel access for users transitioning between platforms.

Schedule a partner evaluation call

EPC Group has held Microsoft Solutions Partner status since 2003 and completed 11,000+ enterprise Microsoft engagements. Talk to a migration architect about your org size, compliance requirements, and timeline. Call (888) 381-9725 or request a 30-minute discovery call.