Migrate to Exchange Online with Confidence
EPC Group has successfully migrated 3.7 million+ mailboxes from on-premises Exchange to Microsoft 365, as well as tenant-to-tenant Exchange Online migrations across Microsoft 365 tenants, with zero data loss and minimal downtime.
Exchange Migration Services
We handle all types of Exchange migrations, from simple cutover migrations to complex hybrid deployments.
On-Premises to Cloud
Migrate from Exchange Server 2010/2013/2016/2019 to Exchange Online with staged or cutover approach.
- minimal-disruption migration
- Data integrity verification
- Mailbox size optimization
- Archive migration
Hybrid Exchange
Maintain coexistence between on-premises Exchange and Exchange Online during transition.
- Seamless coexistence
- Free/busy calendar sharing
- Unified GAL
- Phased user migration
Tenant-to-Tenant Migration
Consolidate mailboxes during mergers, acquisitions, or organizational restructuring.
- Cross-tenant migration
- Mailbox mapping
- Permission preservation
- Archive consolidation
Why Choose EPC Group for Exchange Migration?
29 years of Microsoft ecosystem expertise, with specialized focus on enterprise Exchange deployments.
Zero Data Loss Guarantee
Our migration process includes multiple verification checkpoints to ensure 100% data integrity.
Minimal Downtime
Strategic migration windows and hybrid coexistence minimize impact on business operations.
Compliance-First Approach
HIPAA, SOC 2, and FedRAMP-aligned migrations with full audit trails and documentation.
Expert Project Management
Dedicated project manager, technical lead, and 24/7 support throughout migration lifecycle.
Our Proven Migration Process
A structured, 5-phase approach that has successfully migrated over 10,000 mailboxes.
Discovery & Assessment
Inventory current Exchange environment, mailbox sizes, public folders, and custom configurations. Identify migration blockers and optimization opportunities.
Planning & Design
Create detailed migration plan, timeline, and rollback procedures. Design hybrid architecture if needed. Obtain stakeholder sign-off.
Pilot Migration
Migrate small test group (10-20 users) to validate process, identify issues, and refine procedures before full rollout.
Batch Migration
Execute phased migration in scheduled maintenance windows. Monitor progress in real-time. Verify data integrity at each checkpoint.
Post-Migration Support
User training, issue resolution, decommissioning of legacy infrastructure. 30-day hypercare support included.
Ready to Migrate Your Exchange Environment?
Schedule a free migration assessment. We'll analyze your current environment and provide a detailed migration roadmap with cost estimates.
Exchange Migration Consulting: On-Premises to Exchange Online
EPC Group has migrated 3.7 million+ mailboxes from on-premises Exchange to Microsoft 365 — with zero data loss. We handle cutover, staged, hybrid, and tenant-to-tenant Exchange migrations for organizations of any size. Compliance-first approach for HIPAA, SOC 2, and FedRAMP environments.
Key facts
- 3.7 million+ mailboxes migrated to Microsoft 365 by EPC Group.
- Zero data loss guarantee across all migration types.
- Migration approaches: cutover (under 150), staged (large on-prem), hybrid (coexistence), IMAP (non-Exchange).
- Microsoft Solutions Partner — Modern Work designation. 29 years of Exchange experience.
- Compliance: HIPAA, SOC 2, FedRAMP — compliance holds transfer correctly.
Exchange migration services
EPC Group manages the full Exchange migration lifecycle — from assessment through go-live and hypercare support.
On-premises to Exchange Online
Migration from Exchange Server to Exchange Online is the most common scenario. EPC Group uses the appropriate migration method based on mailbox count and business requirements.
- Cutover migration — all mailboxes at once. Best for under 150 mailboxes. Fastest method. Takes 1–2 weeks.
- Staged migration — batches of mailboxes over time. On-premises Exchange stays active. Best for 150–2,000 mailboxes. Takes 4–8 weeks.
- Hybrid migration — coexistence between on-premises and cloud. Best for 2,000+ mailboxes or long phased timelines. Takes 8–16 weeks.
Hybrid Exchange
A hybrid Exchange configuration connects on-premises Exchange with Exchange Online. Users in both environments appear in a single Global Address List. Mail routes correctly between on-premises and cloud mailboxes.
Hybrid is the preferred approach for enterprises that need:
- A phased migration timeline of more than 8 weeks.
- Coexistence for Dynamics 365 or legacy integrations that require on-premises Exchange.
- Long-term hybrid operation (some mailboxes permanently on-premises).
Tenant-to-tenant migration
Tenant-to-tenant migration moves mailboxes between two Microsoft 365 tenants. This is needed for mergers, acquisitions, divestitures, and organizational restructuring.
- EPC Group handles tenant-to-tenant migrations with BitTitan MigrationWiz or native Microsoft Cross-Tenant Migration tools.
- All mail, calendar, contacts, and compliance holds migrate correctly.
- DNS cutover, MX record transitions, and user communication are managed as part of the engagement.
Why choose EPC Group for Exchange migration?
Zero data loss
EPC Group validates data integrity after every migration wave. We use checksum verification and item-count reconciliation before marking a wave complete. No mailbox is cutover until validation passes.
Minimal downtime
Staged and hybrid migrations maintain continuous mail flow throughout. Users experience no downtime. For cutover migrations, we pre-stage data before the cutover window to minimize the service interruption to under 30 minutes.
Compliance-first approach
For regulated environments, compliance controls migrate correctly or are re-established in Exchange Online before users are cutover.
- Litigation holds and in-place holds transfer to Exchange Online retention policies.
- DLP policies are configured in Exchange Online before migration begins.
- HIPAA BAA is validated before any PHI-containing mailboxes migrate.
- FedRAMP environments deploy to GCC or GCC High based on classification requirements.
Frequently asked questions
How many mailboxes has EPC Group migrated?
EPC Group has migrated 3.7 million+ mailboxes from on-premises Exchange to Microsoft 365, and between Microsoft 365 tenants. All migrations completed with zero data loss and minimal downtime.
What migration approach should I use?
Under 150 mailboxes: use cutover. 150–2,000 mailboxes: use staged migration. Over 2,000 mailboxes or long timelines: use hybrid. Migrating from Gmail or non-Exchange systems: use IMAP. Mergers and divestitures: use tenant-to-tenant.
Does EPC Group guarantee zero data loss?
Yes. EPC Group validates data integrity after every migration wave using checksum verification and item-count reconciliation. No mailbox is cutover until validation confirms complete, accurate data transfer.
What happens to compliance holds during migration?
EPC Group maps all litigation holds, in-place holds, and retention policies from on-premises Exchange to equivalent Exchange Online configurations before migration. For HIPAA, SOC 2, and FINRA clients, we validate compliance controls in Exchange Online before any production mailboxes migrate.
Plan your Exchange migration
Talk to an EPC Group Exchange migration specialist. Call (888) 381-9725 or request a 30-minute discovery call.