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Microsoft 365 Migration: Complete Step-by-Step Guide for 2025

#microsoft365 #migration #enterprise #email

Migrating to Microsoft 365 can transform how your organization works. This guide covers everything from planning to post-migration optimization.

Pre-Migration Planning

1. Inventory Your Current Environment

Before migrating, document:

  • Number of mailboxes
  • Total data size
  • Custom domains
  • Third-party integrations
  • Compliance requirements (HIPAA, SOC2, etc.)

2. Choose Your Migration Method

Method Best For Complexity Downtime
Cutover <150 mailboxes Low 1-2 days
Staged 150-2000 mailboxes Medium Weeks
Hybrid 2000+ mailboxes High Minimal
IMAP Non-Exchange servers Low Days
Third-party Complex scenarios Varies Minimal

3. Prepare Your Domain 

# DNS records needed
MX:    example-com.mail.protection.outlook.com
TXT:   v=spf1 include:spf.protection.outlook.com -all
CNAME: autodiscover -> autodiscover.outlook.com
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Migration Steps

Step 1: Set Up Microsoft 365 Tenant

  1. Purchase licenses at admin.microsoft.com
  2. Add and verify your domain
  3. Create user accounts (or sync from AD)

Step 2: Configure Connectors (Hybrid)

For hybrid migrations, set up send and receive connectors between on-premises Exchange and Microsoft 365.

Step 3: Migrate Mailboxes 

# PowerShell for batch migration
New-MigrationBatch -Name "Batch1" -SourceEndpoint $Endpoint \
  -CSVData ([System.IO.File]::ReadAllBytes("users.csv")) \
  -TargetDeliveryDomain "company.mail.onmicrosoft.com"

Start-MigrationBatch -Identity "Batch1"
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Step 4: Update DNS

Switch MX records to Microsoft 365 when ready:

MX 0 company-com.mail.protection.outlook.com
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Step 5: Post-Migration Tasks

  • Reconfigure mobile devices
  • Update Outlook profiles
  • Test email flow
  • Archive old servers
  • Train users on new features

Common Migration Scenarios

Google Workspace to Microsoft 365

Use the built-in Google Workspace migration tool:

  1. Admin Center → Data migration → Gmail
  2. Authorize access with admin credentials
  3. Select users and data types
  4. Start migration (runs in background)

Full guide: Google Workspace to M365 Migration

Exchange Server to Microsoft 365

For on-premises Exchange 2016/2019:

  1. Set up hybrid configuration wizard
  2. Move mailboxes in batches
  3. Decommission on-premises servers

Full guide: Exchange to M365 Migration

Tenant-to-Tenant Migration

For M&A or rebranding scenarios:

  1. Cross-tenant migration (preview feature)
  2. Third-party tools (BitTitan, Quest)
  3. Manual export/import (small orgs)

Full guide: Tenant-to-Tenant Migration

Cost Estimation

Use migration calculators to estimate:

  • Duration based on data size
  • License costs
  • Consulting fees

Try our Migration Calculator

Tips for Success

  1. Communicate early: Inform users 2 weeks before migration
  2. Migrate in waves: Don't do everyone at once
  3. Keep old system running: 30-day parallel operation
  4. Test thoroughly: Create test accounts first
  5. Document everything: For future audits

Conclusion

A well-planned migration minimizes disruption and sets your organization up for success with Microsoft 365's collaborative features.

Need expert migration help? Medha Cloud has completed 1,200+ successful Microsoft 365 migrations. Get a free assessment today.

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