How to Migrate Email to Microsoft 365 (No Downtime, 2026)
Prepare
Inventory mailboxes, pick the right plan, verify your domain in Microsoft 365, and set up users before touching mail flow.
Migrate and cut over
Pre-sync mailboxes, then switch MX records at a quiet time. Existing mail follows; new mail arrives in the new system.
Verify
Confirm send/receive, calendars and shared mailboxes, and remove the old system once stable. IT Cares does migrations with zero lost messages.
Action checklist
- ✅ Inventory all mailboxes and aliases
- ✅ Choose the right Microsoft 365 plan
- ✅ Verify your domain before cutover
- ✅ Pre-sync mail, then switch MX off-hours
- ✅ Test send/receive and calendars after
FAQ
Can I move to Microsoft 365 without losing emails?
Yes. Pre-sync mailboxes, switch MX records at a quiet time, and verify afterward. Done in this order, no messages are lost and downtime is near zero.
How long does a Microsoft 365 email migration take?
A small business is usually fully migrated within a day or two, with the actual cutover scheduled for a quiet period to minimize disruption.
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