Email Migration to Microsoft 365 —
Zero-Downtime Cutovers
Fixed-fee email migrations from Exchange on-prem, Google Workspace, hosted mail, and between M365 tenants. Pre-staged DNS, phased user waves, Defender for Office baseline, and an evidence package at cutover. Microsoft AI Cloud Partner.
Six Source Patterns, One Destination
Whatever you're moving from — on-prem Exchange, Google Workspace, legacy hosts, or another M365 tenant — the migration ends the same way: a clean M365 tenant with a hardened mail security baseline.
Exchange On-Premises → M365
Full hybrid or staged cutover from Exchange 2010, 2013, 2016, or 2019. Autodiscover coexistence, MRSProxy tuning, calendar coexistence, and phased user batches — coordinated against change windows so sends and receives never stop.
Google Workspace → M365
Mail, calendar, contacts, and Drive migrations from Google Workspace. Calendar coexistence during cutover, Hangouts/Chat → Teams history where available, and DNS/MX sequencing so no mail is lost in flight.
Tenant-to-Tenant (M&A, Divestiture)
Cross-tenant migrations after acquisitions, divestitures, or brand consolidations. Mailboxes, calendars, Teams, SharePoint, and OneDrive moved with full fidelity — plus identity rehoming and guest-access cleanup in both tenants.
IMAP & Legacy Mail Host → M365
IMAP-based migrations from GoDaddy, Rackspace, hosted Exchange, cPanel, and other legacy providers. Calendar and contact reconstruction where needed, PST ingest, and MX cutover without downtime windows.
Hybrid → Cloud-Only (Exchange Decom)
Retiring your last on-prem Exchange server. Final mailbox moves, public folder migration, connector cleanup, Hybrid Configuration Wizard decommission, and Exchange schema retirement — plus post-cutover mail flow validation.
PST Remediation & Archive Ingest
Inventory loose PSTs across laptops and file shares, ingest into M365 archive mailboxes or Purview, apply retention labels, and retire PST sprawl — often paired with a migration but available as a standalone engagement.
Six Stages, One Written Runbook
Every migration runs the same disciplined stages — sized to your environment and compliance requirements.
Pre-Migration Discovery
Mail-flow mapping, mailbox inventory, distribution list and shared-mailbox audit, connector and mail-relay census, calendar-dependency map, and a go/no-go risk register before any config change.
Migration Design & DNS Plan
Batch strategy, coexistence design, DNS/MX cutover plan with TTL pre-staging, SPF/DKIM/DMARC hardening, and a written cutover runbook reviewed with your IT leadership before execution.
Identity & Licensing Alignment
Entra ID sync (Entra Connect or Cloud Sync), UPN remediation where needed, license assignment by persona, shared mailbox vs. licensed mailbox modeling, and MFA rollout coordinated against the migration timeline.
Batched Execution
Pilot batch first, then phased user waves sized to your change windows. Per-user validation, Outlook profile repair where needed, mobile device re-enrollment, and an active-monitoring desk during every cutover.
Mail Security & Compliance
Defender for Office 365 policy deployment, anti-phish tuning, safe attachments / safe links configuration, Purview retention baseline, and journaling if your compliance regime requires it — all live before cutover completes.
Post-Migration Evidence
Completion report with mailbox counts, message counts migrated, MX/DNS cutover log, Defender baseline attestation, and a written evidence package for audit or cyber insurance.
From Discovery to Cutover in 4–8 Weeks
Predictable fixed-fee engagement with written deliverables at every stage.
Discovery
Mail-flow mapping, mailbox inventory, DNS and MX audit, distribution list and shared-mailbox review, connector and relay census, and initial risk register. Fixed-fee deliverable.
Design & Runbook
Batch strategy, DNS cutover plan, Entra ID sync design, mail security baseline, and a written cutover runbook — signed off by your IT leadership before any production change.
Pilot & Waves
Pilot batch first, then phased user waves aligned to your change windows. Per-user validation, Outlook profile repair, mobile re-enrollment, and coexistence monitoring until every user is in M365.
Cutover & Decom
Final MX cutover, Exchange on-prem decommission where applicable, mail security baseline verification, and post-migration evidence package. Handoff to your team or ICS M365 Management for ongoing operations.
Fixed-Fee. Per-Seat. No Surprise Change Orders.
Email migration is fixed-fee with a per-seat rate and a base engagement fee. Every proposal includes written scope, cutover runbook, and evidence package before work starts. Microsoft licensing is sized and procured separately — often alongside the migration.
The Microsoft Practice Behind Every Migration
Microsoft 365 Management
Take over operations after cutover — tenant administration, security, user lifecycle, and periodic reviews so the migration doesn't become maintenance debt.
Learn More →Entra ID Hardening
Pair migration with a hardened identity baseline — Conditional Access, PIM, and MFA enforcement delivered on the new tenant before full production cutover.
Learn More →Microsoft 365 Licensing
Size your M365 licensing against the migrated estate — E3 vs E5, Business Premium, F-SKUs for frontline, and CSP management.
Learn More →Email Migration — FAQ
How long does a Microsoft 365 email migration take?+
Most engagements run 4–8 weeks end-to-end depending on seat count, source platform, and change-window constraints. Under 100 seats typically complete in 4 weeks; 500–1,500 seats run 6–8 weeks with phased waves. Tenant-to-tenant migrations post-M&A can compress or extend based on legal timing constraints.
Will our email go down during the cutover?+
No. Every migration we run is designed for zero mail-flow downtime. MX records are pre-staged with low TTLs, coexistence is maintained through the migration window, and final cutover happens with dual-routed mail flow so messages arriving at either endpoint are correctly delivered. Users may see a brief Outlook restart and a one-time re-authentication prompt — that's it.
What about calendars and free/busy during the migration?+
Calendar coexistence is designed in from day one. Exchange hybrid provides native free/busy between cloud and on-prem during coexistence. Google migrations use calendar sharing plus a coexistence tool during the cutover period. Tenant-to-tenant migrations use cross-tenant calendar sharing in M365 where your Conditional Access policies allow it.
How do you handle shared mailboxes, distribution lists, and calendars?+
Each is audited pre-migration. Shared mailboxes move with full permissions and delegates preserved. Distribution lists either migrate as DLs or convert to Microsoft 365 Groups / Teams depending on usage. Room and resource mailboxes keep booking policies and delegate approvers. Calendar publishing and external-sharing settings are reconfigured on the cloud side to match current behavior.
We have years of PSTs scattered across laptops. Can you clean those up?+
Yes. PST remediation is either bundled with the migration or run as a standalone engagement. We inventory PSTs across endpoints and file shares, ingest into user archive mailboxes or Purview (depending on size, retention needs, and compliance regime), apply retention labels, and retire the PST sprawl. Often this is the first time an organization has had a real retention policy on historical mail.
Do you help with tenant-to-tenant migrations after an acquisition or divestiture?+
Yes. Tenant-to-tenant is a significant portion of our email migration work. We handle mailbox moves, calendar and contact migration, SharePoint and OneDrive content migration, Teams migration where feasible, identity rehoming in Entra ID, and guest-access cleanup on both sides. Typical M&A engagement timing is 6–12 weeks depending on legal close timeline.
How do you price email migrations?+
Fixed-fee, per-seat + base engagement fee. Every proposal includes a written scope, cutover runbook, and evidence package before work starts. Licensing is separate and typically handled alongside migration — see our Microsoft 365 Licensing page.
Can you run the Microsoft 365 environment after the migration?+
Yes. Many clients start with a fixed-fee migration and transition to ongoing Microsoft 365 Management — tenant administration, security, user lifecycle, and periodic reviews. Others hand off the hardened tenant to their internal team with a written runbook. Both are equally supported.
Ready to Migrate to Microsoft 365?
Fixed-fee engagement. Zero-downtime design. Evidence package at cutover. Typical migrations run 4–8 weeks with a written runbook your team can follow from pilot through Exchange decommission.