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Moving from Gmail to Exchange Online sounds simple until you actually start doing it. Between IMAP limits, authentication issues, and data loss risks, it’s easy to waste hours on what should’ve been a straightforward transfer. So here’s the no-fluff version of how to get it done safely.

Before You Start Gmail to Exchange Online Migration

Make sure you’ve covered the basics:

  • List all the Gmail accounts you’ll be moving.
  • Check mailbox sizes — large ones need more time.
  • Enable IMAP in Gmail.
  • If users have 2-Step Verification, create app passwords.
  • Get admin access on both sides (Google and Microsoft 365).
  • Decide if you’re moving only emails or also contacts and calendars.

Manual Gmail to Exchange Online Migration (Basic Option)

Exchange Online lets you migrate mailboxes using IMAP. It works, but it’s limited — you’ll only get emails, not contacts or calendars.

  1. In Exchange Admin Center, create a migration endpoint using imap.gmail.com.
  2. Add the Gmail accounts and passwords (or app passwords) in a CSV file.
  3. Start a new IMAP migration batch and test with a few users first.
  4. Once the batch completes, check the folder structure and message count.
  5. When everything looks fine, run a final sync and then cut over your MX records.

You can move mail this way, but Gmail labels will turn into folders, and some message flags or read statuses may not survive. Expect a bit of cleanup later.

Contacts and Calendar Migration

IMAP can’t move them. You’ll need to:

  • Export contacts from Gmail as a CSV and import them in Outlook.
  • Export calendars as .ics files and import them manually in Exchange Online.

It’s slow and can mess up recurring events — test a few accounts before doing this for everyone.

Common Problems

  • Authentication fails: use app passwords or an OAuth-based tool.
  • Timeouts or throttling: migrate in smaller batches or off-hours.
  • Missing attachments: check size limits or re-sync the batch.
  • Label chaos: Gmail labels don’t translate perfectly — prepare users for folder changes.

Why is Tool Better for Gmail to Exchange Online Migration?

Manual IMAP migration is fine for 5–10 mailboxes. Beyond that, you’ll spend more time fixing sync errors than actually migrating. A proper migration utility will:

  • Handle Authentication automatically.
  • Map labels more cleanly.
  • Run incremental (delta) syncs.
  • Generate logs and reports.

After the Migration

  • Update MX, SPF, and DKIM records.
  • Reconfigure Outlook or mobile profiles.
  • Verify mail flow for a few users.
  • Keep Gmail accounts in read-only mode for a couple of days before deletion.
  • Inform users about folder differences and where to find old mail.

Final Thoughts

There’s no “perfect” Gmail to Exchange Online migration — just cleaner and riskier ways. If you have time to babysit IMAP batches, do it manually. If not, let a reliable tool handle it. The key is to plan, test, and never skip a pilot batch.