Office 365 Email Migration via MigrationWiz

Section: Email & Microsoft 365 Tags: migration, migrationwiz, office365, exchange, email, domain, mx, dns Source tickets: #16277, #25616, #23113 Confidence: High — standard Purple Computing migration procedure, used across many clients

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Overview

This is the standard Purple Computing procedure for migrating a client's email from a third-party host (cPanel, Cobweb, SynStar, Messagelabs, hosted Exchange) to Microsoft 365. Uses MigrationWiz (BitTitan) for the mailbox data transfer. Typical project time: 1–2 days for a small business (up to 10 mailboxes), spread across pre-migration, cutover, and device setup.

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Prerequisites

Before starting:

• [ ] M365 tenant created with appropriate licences assigned (Business Basic or Standard minimum)
• [ ] Admin access to the source mail host (control panel or admin credentials)
• [ ] Access to the domain registrar (to update MX and DNS records)
• [ ] MigrationWiz / BitTitan account (https://migrate.bittitan.com)
• [ ] List of all mailboxes to migrate with source credentials
• [ ] Agreed cutover time with client (recommend a Friday evening or weekend)
• [ ] Confirm any shared mailboxes, aliases, distribution lists — these need separate handling

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Phase 1 — M365 Tenant Preparation

• Log in to https://admin.microsoft.com
• Go to Users → Active Users — create accounts for each user (use the .onmicrosoft.com domain initially — do NOT switch the primary domain yet)
• Assign Exchange Online licences to each user
• Verify the domain in M365: Settings → Domains → Add domain — add the client's domain and complete the TXT verification record at the registrar

- TXT name: @ (or leave blank if registrar does not support @) - TXT value: MS=ms######## (shown in the wizard) - Wait for verification before proceeding

• Do NOT update MX records yet — email continues flowing to the old host during migration

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Phase 2 — MigrationWiz Setup

• Log in to https://migrate.bittitan.com
• Create a new Mailbox migration project
• Source endpoint: select the source mail type (IMAP, Exchange, cPanel) and enter admin credentials
• Destination endpoint: select Exchange Online (Modern Auth) and enter M365 admin credentials
• Add mailboxes: for each user, add a migration item:

- Source: olduser@olddomain.com + source password - Destination: user@clientdomain.onmicrosoft.com

• Pre-stage migration (run before cutover): select all items → Start Migration → choose "Full Migration"

- This copies all existing email, calendar, contacts into M365 without interrupting service - Allow 4–24 hours for large mailboxes (>10GB)

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Phase 3 — Cutover (MX Switch)

Run this step at the agreed cutover time (ideally evening/weekend).

• Verify the pre-stage is complete in MigrationWiz — all items show "Success"
• Log in to the domain registrar
• Update MX records to point to M365:

- Remove old MX records - Add: clientdomain.com MX 0 clientdomain-com.mail.protection.outlook.com (exact value from M365 → Settings → Domains → DNS records)

• Update Autodiscover CNAME: autodiscover → autodiscover.outlook.com
• Update SPF TXT record: v=spf1 include:spf.protection.outlook.com -all
• Wait for MX propagation (typically 15–60 minutes — check at https://mxtoolbox.com)
• Once MX is pointing to M365: run a final delta migration in MigrationWiz (catches any email that arrived during the switch window)
• Contact the old host to request the domain release from their M365 portal (critical if they are a Microsoft reseller — they may need to detach the domain before it can be used in your tenant)

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Phase 4 — Device Configuration

For each user's Mac:

• Open Outlook → Preferences → Accounts — remove the old account
• Add new account: enter the user's M365 email — Autodiscover will configure Exchange settings automatically
• Enter the M365 password when prompted
• Confirm email arrives and calendar syncs

For iPhone/iPad:

• Settings → Mail → Accounts — remove old account
• Add new account: Microsoft Exchange → enter email and M365 password
• Or: install and configure the Outlook for iOS app (recommended for M365)

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Phase 5 — Post-Migration Checks

• [ ] Test send and receive for every migrated mailbox
• [ ] Confirm calendar entries migrated (spot-check a few upcoming appointments)
• [ ] Confirm contacts migrated
• [ ] Shared mailboxes and distribution lists configured in M365 admin
• [ ] Old mail host notified to cancel subscription (confirm with client timing)
• [ ] MX propagation verified: mxtoolbox.com shows only M365 MX record
• [ ] Client shown how to log in to https://outlook.office.com

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Verification

Send an email from an external address to the client's domain. Confirm it arrives in M365 within 2 minutes. Reply from M365 and confirm the external party receives it. Check SPF/DKIM pass status at https://mxtoolbox.com/emailheaders.aspx.

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Common Issues

IssueCauseFix ------------------- Migration fails for one mailboxSource password incorrectReset password at source host, update in MigrationWiz Domain won't verify in M365Old host owns it in their M365 tenantContact old host to release the domain from their tenant first Email going to old host after MX changeDNS TTL not expiredWait; check with mxtoolbox.com Autodiscover fails on MacAutodiscover CNAME not yet propagatedAdd the account manually (Exchange server: outlook.office365.com) Shared mailboxes missingNot yet configured in M365In admin.microsoft.com → Groups → Shared mailboxes → Add

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Related

• Article: Email Not Sending — Hosted Exchange / O365 — for post-migration delivery issues
• Article: New User Onboarding — M365 Account + Mac Setup — for adding new users after migration