June 10, 2026 · 5 min read · Deepbluework Team

How to Migrate Your Business Email Without Losing Messages

Switching email providers — from Google Workspace to Deepbluework, or from one host to another — does not have to mean losing years of messages. With the right plan, you can migrate cleanly with minimal downtime.

This guide covers a proven migration workflow used by small teams moving to custom domain email platforms.

Before you start: inventory your current setup

Document the following:

• Current provider (Google Workspace, Microsoft 365, cPanel, etc.)
• Number of mailboxes and their addresses
• DNS registrar where your domain is managed
• Email clients in use (Outlook, Apple Mail, mobile apps)
• Integrations — CRM, ticketing, marketing tools sending from your domain
• Shared mailboxes or aliases (e.g. hello@ forwarding to you@)

Phase 1: Prepare the new provider

1. Create accounts on your new email platform (e.g. Deepbluework).
2. Add all users who need mailboxes.
3. Note the MX, SPF, DKIM, and DMARC records the new provider requires — but do not change DNS yet.

Important: Keep your old provider active until migration is complete. Changing MX records too early routes new mail to empty mailboxes.

Phase 2: Copy existing messages

There are three common methods:

Method A: IMAP sync (recommended)

Use an IMAP migration tool or email client to copy messages from old server to new:

1. Connect your email client to the old account via IMAP
2. Connect the same client to the new account via IMAP
3. Drag folders from old to new (or use a migration tool like imapsync)

This preserves folder structure and read/unread status.

Method B: Export/import (MBOX)

1. Export each mailbox from the old provider as MBOX files
2. Import MBOX files into the new provider (if supported)
3. Verify message counts match

Google Workspace supports MBOX export via Google Takeout. Microsoft 365 supports PST export via Outlook.

Method C: Provider migration service

Some providers offer built-in migration from Google or Microsoft. Deepbluework supports standard IMAP import — connect your old account and sync messages into your new mailbox.

Phase 3: Migrate contacts and calendars

• Contacts: Export as vCard (.vcf) or CSV from the old provider, import into the new one.
• Calendars: Export as ICS files from Google Calendar or Outlook, import into the new calendar.

Deepbluework includes calendar and contacts as part of the platform — import ICS/vCard files after mailboxes are created.

Phase 4: Cut over DNS (the critical step)

Schedule DNS cutover during a low-traffic window (evening or weekend):

1. Lower TTL on MX records 24–48 hours before (e.g. set to 300 seconds) for faster propagation
2. Update MX records to point to the new provider
3. Update SPF, DKIM, and DMARC records
4. Verify with your provider's DNS check tool

DNS propagation typically takes 15 minutes to 48 hours. During this window, some mail may still route to the old provider — keep it running for at least 48 hours.

Phase 5: Update email clients

Each user updates their email client settings:

• New IMAP/SMTP server hostnames
• New password (if changed)
• Remove and re-add the account, or update server settings

For mobile devices, remove the old account after confirming the new one works to avoid duplicate notifications.

Phase 6: Verify and decommission

Run this checklist:

• [ ] Send test email to external address (Gmail, Outlook.com) — check inbox, not spam
• [ ] Receive reply — confirm inbound delivery works
• [ ] Check email headers for spf=pass, dkim=pass, dmarc=pass
• [ ] Verify all users can send and receive
• [ ] Confirm migrated messages are accessible in all folders
• [ ] Update email signatures with any new webmail URL
• [ ] Update integrations (CRM, website contact forms) if SMTP credentials changed

After 1–2 weeks of stable operation, cancel the old provider and remove old MX records if any remain.

Minimising downtime

To avoid missing messages during cutover:

1. Keep old provider active for 48–72 hours after DNS change
2. Set up forwarding from old to new during transition (if old provider supports it)
3. Communicate the switch date to your team
4. Use a "migration in progress" auto-reply only if absolutely necessary

Migrating to Deepbluework specifically

Deepbluework is a business email platform designed for straightforward migration:

• IMAP/SMTP on every mailbox — sync from any provider
• Automatic DNS via DomainConnect for SPF, DKIM, DMARC
• First mailbox free — test migration with one user before moving the whole team
• $0.99/user/month for additional team members
• Admin dashboard to add users, groups, and manage DNS from one place

Pricing summary: first mailbox free forever · $0.99/user/month for additional users · 10 GB storage per mailbox · no contracts.

Start your migration with a free mailbox →

When to get help

Consider professional assistance if:

• You have 50+ mailboxes
• You use complex routing rules or shared mailboxes
• You operate in a regulated industry with compliance requirements
• Migration must complete within a strict downtime window

For most small teams, the IMAP sync method above works reliably with a weekend of focused effort.