Migration & CoexistenceIMAP & Third-Party Migration

IMAP & Third-Party Migration

25 mins

Understanding the Concept

IMAP migration allows moving email from any IMAP-compatible email system (Gmail, Yahoo, custom IMAP servers) to Exchange Online. It migrates email messages only—contacts, calendar, and tasks must be migrated separately.

The migration process involves creating a CSV file with user credentials, setting up a migration endpoint, creating a migration batch, and monitoring progress. Each batch can contain up to 50,000 mailboxes.

For complex third-party migrations (Notes, GroupWise, other platforms), Microsoft-recommended third-party migration tools provide richer functionality including calendar, contact, and rule migration.

Key Points

•IMAP migration supports any IMAP-compatible source system

•Only email messages are migrated (not calendar/contacts/tasks)

•CSV file maps source to destination accounts

•Migration endpoint defines source server connection

•Batch migration processes users in groups

•Third-party tools needed for non-IMAP systems

Why This Matters

Many organizations migrate from diverse email platforms. IMAP migration provides a universal method for email migration, while understanding third-party tool options is important for complex multi-platform environments.

Common Mistakes to Avoid

✗Expecting IMAP migration to include calendar and contacts

✗Not pre-creating user accounts and licenses before migration

✗Setting migration batch size too large causing throttling

Interview Discussion Points

💡Describe the complete IMAP migration process

💡Explain how to handle calendar and contact migration from IMAP sources

💡Discuss when to recommend third-party migration tools over native methods

MS-203 Exam Tips

📝Know what IMAP migration does and does not migrate

📝Understand the CSV file format for IMAP migration batches

📝Be familiar with migration endpoint configuration requirements

Hybrid Exchange Configuration

Post-Migration Validation