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Service

Exchange Online
Migration

Move from on-premise Exchange Server to Exchange Online with structured cutover planning, hybrid configuration, and zero-loss data transfer.

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Overview

What this migration involves

Exchange Online migration moves all mailboxes, public folders, distribution lists, and mail flow rules from on-premise Exchange Server to Microsoft cloud-hosted Exchange Online.

CloudyNex manages the full lifecycle: from hybrid deployment configuration through delta synchronisation to final cutover — keeping your email flowing throughout. Still running Exchange 2016 or Exchange 2019? Both reached end of support in October 2025, with extended security updates ending October 2026.

What we migrate
  • All user mailboxes and archives
  • Shared and resource mailboxes
  • Distribution lists and mail contacts
  • Public folders and calendar data
  • Mail flow rules and connectors
  • Hybrid deployment configuration
How It Works

The migration path

A clear, structured path from source to destination — with CloudyNex managing every step.

Exchange Server (On-Prem)
Your current mail server
via CloudyNex
CloudyNex
Migration engine
arrives at
Exchange Online
Cloud-hosted · always on
Business Challenges

What makes this migration complex

01
Hybrid configuration complexity

Running Exchange on-premise alongside Exchange Online requires careful hybrid configuration to maintain mail flow and coexistence without gaps or routing failures.

02
Legacy rules and connectors

Years of accumulated mail flow rules, transport rules, and custom connectors must be documented and migrated to avoid silent delivery failures post-cutover.

03
Cutover timing

The MX record change is the critical moment. Pre-staging and precise scheduling minimise the window where mail could be delayed or lost.

Our Process

How we run the migration

01 — Audit
Environment audit
Full audit of Exchange topology, mailbox sizes, public folders, connectors, and third-party integrations.
02 — Setup
Hybrid deployment
Configure Exchange Hybrid to enable coexistence and mail flow between on-premise and Exchange Online.
03 — Planning
Migration batching
Mailboxes batched by department or priority. Cutover schedule and rollback plan documented and agreed.
04 — Pre-stage
Mailbox sync
Initial mailbox content synced to Exchange Online while users remain on-premise. Incremental sync continues.
05 — Cutover
MX cutover
Final sync, MX record update, Autodiscover update, and client reconfiguration — executed to a precise schedule.
06 — Hypercare
Post-migration
7-day monitoring. User issues triaged and resolved. Source environment maintained until full sign-off.

Need help with this migration?

Contact our migration specialists today.

Request a Free Consultation
FAQ

Frequently asked questions

Small organisations under 100 mailboxes typically complete in a few days. Larger environments with complex hybrid requirements may take two to four weeks including planning.
Yes. We configure a hybrid deployment allowing both environments to coexist. Users can be migrated in batches while others remain on-premise.
No. We pre-stage mailbox data so it is synced before cutover. The live window is measured in minutes. The source is kept intact until migration is verified and signed off.
Get Started

Ready to move to
Exchange Online?

Tell us about your environment. We will assess the complexity and give you a clear, written migration plan.

Request a Free Consultation About CloudyNex

No commitment required · Response within one business day · sales@cloudynex.co