Migration Readiness Checklist

Use this phased checklist to guide your Exchange Server migration project from initial assessment through post-migration cleanup. Click any item to track progress — your selections are saved automatically in the browser.

Table of contents

Phase 1 — Current State Assessment
Phase 2 — Migration Planning
Phase 3 — Pre-Migration Preparation
Phase 4 — Migration Execution
Phase 5 — Post-Migration & Cleanup

Phase 1 — Current State Assessment

Complete this phase before choosing a migration path. Decisions made here drive all downstream planning.

Server Inventory

Document all Exchange Server versions and editions in use
Record server hardware specifications (CPU, RAM, disk, network)
Identify server roles (Mailbox, Edge Transport, DAG membership)
Capture OS version and patch level for each server
List all installed Exchange Cumulative Updates (CUs)
Document Database Availability Group (DAG) topology
Identify co-located workloads on Exchange servers

Mailbox Audit

Export full mailbox inventory (size, item count, last logon)
Identify shared mailboxes, room/equipment mailboxes, and discovery mailboxes
Locate inactive and soft-deleted mailboxes
Audit mailbox archive sizes and archive policies
Identify users with mailboxes over 50 GB (cloud migration impact)
Review public folder usage and size
Document distribution groups, dynamic distribution groups, and mail-enabled security groups

Mail Flow & Connectors

Map all Send Connectors and Receive Connectors
Document SMTP relay configurations (applications, printers, scanners)
Identify third-party anti-spam/anti-malware gateways
Review accepted domains and email address policies
Document mail flow rules (transport rules)
Audit journal rules and compliance archive settings

Client & Integration Assessment

Identify all Outlook versions in use across the organization
Locate mobile device users (ActiveSync, Outlook Mobile)
Document Outlook on the Web (OWA) usage patterns
Identify third-party applications authenticating to Exchange (ERP, CRM, EWS, monitoring tools)
Review MAPI/CDO-based legacy applications
Document any applications using Basic Authentication
Review line-of-business apps with Exchange Web Services (EWS)

DNS & Certificates

Audit all Exchange-related DNS records (Autodiscover, MX, SPF, DKIM, DMARC)
Review SSL/TLS certificate expiry dates and subject alternative names (SANs)
Document certificate authority (CA) used — internal vs. public
Verify certificate coverage for all Exchange namespaces

Phase 2 — Migration Planning

Do not begin technical implementation until Phase 2 is complete. Decisions here are expensive to reverse mid-migration.

Migration Path Selection

Review migration options and select primary path
Confirm cloud readiness (internet bandwidth, latency, licensing budget)
Validate data-sovereignty and compliance requirements
Obtain executive and stakeholder sign-off on migration strategy
Identify any regulatory constraints (GDPR, HIPAA, FedRAMP, ISO 27001)

Project Planning

Define project sponsor, project manager, and technical leads
Establish migration steering committee
Build detailed project plan with milestones and dependencies
Define pilot group (10–50 representative users)
Create mailbox migration waves (prioritized by department and risk)
Schedule migration during low-activity windows
Define rollback criteria and rollback procedure for each wave
Establish communication plan for end users and IT

Licensing & Procurement

Validate current Exchange Server license compliance
Obtain Microsoft 365 or Exchange SE license quotes
Purchase licenses with sufficient lead time before migration
Assign licenses to pilot users in advance of testing
Review Software Assurance entitlements (if applicable)

Infrastructure Preparation

Assess Active Directory health (schema version, replication, domain functional level)
Verify AD Connect/Entra Connect is deployed for hybrid identity (if using Microsoft 365)
Confirm DNS delegation for Autodiscover in hybrid mode
Evaluate internet egress capacity for cloud migration workloads
Plan network firewall rules for hybrid connector (if applicable)

Phase 3 — Pre-Migration Preparation

Environment Setup

Deploy test/staging environment for migration validation
Configure Microsoft 365 tenant — verify domain ownership in admin center
Configure Entra ID Connect (formerly Azure AD Connect) sync
Enable and configure Exchange Hybrid Configuration Wizard
Deploy Exchange Server SE — prepare new server hardware or virtual machines
Install and configure Exchange SE in coexistence mode
Validate hybrid mail flow end-to-end in test environment

Security & Compliance Baseline

Enable Modern Authentication on current Exchange if not already active
Disable Basic Authentication for migrating users
Configure multi-factor authentication (MFA) for pilot users
Review and update Conditional Access policies (if using Entra ID)
Confirm data loss prevention (DLP) policies transfer or equivalent exists in target

Backup & Recovery

Verify full backup of all Exchange databases
Test mailbox restore from backup in test environment
Document recovery time objective (RTO) and recovery point objective (RPO)
Retain Exchange backups for at least 90 days post-migration

User & Help Desk Readiness

Prepare user communication template (announce migration dates)
Train help desk on expected support tickets (Outlook profile, Autodiscover issues)
Create FAQ document for end users
Set up dedicated migration support channel (Teams, ticketing queue)
Run pilot user briefing session

Phase 4 — Migration Execution

Pilot Wave (Week 1–2)

Migrate pilot group (IT staff and volunteer early adopters)
Validate Autodiscover connectivity for all client types
Confirm mobile device ActiveSync provisioning
Test calendar sharing and free/busy information
Validate mail flow (internal, external, relays)
Verify public folder access if retained
Confirm archive mailbox access
Collect and review pilot feedback before proceeding

Production Waves

Execute migration waves per approved schedule
Monitor migration queue and throughput daily
Resolve any failed migrations before proceeding to next wave
Update help desk on wave completion and expected tickets
Validate each wave with spot-check user calls

Mail Flow Cutover

Update MX records to point to Microsoft 365 (Exchange Online Protection) or new server
Update SPF, DKIM, and DMARC DNS records
Verify inbound mail delivery to all migrated mailboxes
Validate outbound mail signing and DMARC alignment
Monitor mail flow for 48 hours post-MX change
Update SMTP relay configurations for applications/devices

Phase 5 — Post-Migration & Cleanup

Validation & Sign-Off

Confirm 100% of mailboxes are migrated and verified
Run post-migration user satisfaction survey
Validate all application integrations are functional
Confirm compliance archive and journaling is operational
Obtain formal business sign-off on migration completion

Decommissioning

Remove legacy Exchange servers from DAG (if applicable)
Uninstall Exchange from legacy servers following Microsoft guidance
Do NOT delete Exchange server objects from Active Directory without proper uninstall
Reclaim server hardware or decommission VMs
Remove or archive legacy Exchange backup jobs
Update CMDB and infrastructure documentation
Cancel unused on-premises Exchange-related licenses or subscriptions

Documentation

Update network diagrams to reflect new mail infrastructure
Document new MX, SPF, DKIM, DMARC configuration
Record new admin procedures for Exchange Online or Exchange SE
Archive migration project documentation for audit purposes

Keep legacy Exchange servers accessible (but offline or isolated) for at least 30 days post-migration to handle edge cases such as delayed mail delivery, legal hold review, or rollback needs.