Key takeaways
- Start by inventorying mailboxes, aliases, forwarding rules and devices.
- DNS record changes should be planned outside critical working hours.
- MFA and email protection policies should be part of the migration, rather than a later addition.
- A pilot test reduces the risk of errors affecting the entire organisation.
What should you prepare before migration?
List domains, mailboxes, mailbox sizes, archives, calendars, mobile devices, forwarding rules and applications that send messages. Also establish which data must be retained and who will approve the cutover.
DNS
Records indicating where email is delivered and how the server authenticates messages.
MX
A record specifying the server that receives email for the domain.
Autodiscover
A mechanism that simplifies automatic Outlook configuration.
Migration stages
- Inventory. Gather accounts, aliases, devices and dependencies.
- Tenant design. Define domains, names, groups, licences and policies.
- Pilot. Move several mailboxes and test email, calendars and devices.
- Data migration. Carry out the move in stages and monitor errors.
- DNS cutover. Change MX, SPF, DKIM and DMARC records according to plan.
- Stabilisation. Monitor deliverability, support requests and sign-ins.
Common mistakes and risks
No forwarding-rule inventory
Messages may be sent to mailboxes that do not exist or are not controlled.
No DNS test
An incorrect record can delay or reject email.
Migration without MFA
Moving accounts without improving their protection preserves existing risks.
What determines the cost?
The cost depends on the number of mailboxes, data volume, source system, archives, number of domains, devices and applications, and the scope of security configuration. Testing and user support time must also be included.
Checklist
- The inventory of mailboxes, aliases and forwarding rules is up to date.
- Licences are matched to user roles.
- The domain and DNS records have been prepared.
- The pilot was completed without critical errors.
- MFA and email security are enabled.
- There is a rollback plan and support contact.
Frequently asked questions
Does email stop working during migration?
A well-planned migration limits disruption to the DNS cutover and record propagation.
Can migration be carried out in stages?
Yes. Stages make it possible to test the process and roll out the change to groups of users.
Does Microsoft 365 replace email backup?
No. Retention and recycle bins are useful, but an independent copy makes recovery after an error or incident easier.
Are you planning to change your email platform?
We can prepare a migration plan suited to your number of users, data and working practices.
Let's talk about your IT