Microsoft 365 migration: a checklist before email and DNS cutover
Updating MX records is only one part of moving to Microsoft 365. The real challenge is keeping work flowing across email, calendars, shared files, applications and mobile devices.
1. Inventory the current environment
List domains, mailboxes, aliases, distribution lists, shared mailboxes, file shares and permissions. Identify SMTP-dependent printers, monitoring and business applications. Dependencies missed before migration often become urgent after cutover.
- Licensing and storage review
- Application mail-flow inventory
- DNS and administrative access verification
2. Identity and access strategy
Decide where users are managed, how MFA will work and which access policies are required. Sign-in changes may affect more than email.
- Authentication and MFA choices
- Outlook and mobile setup plan
- Representative pilot users
3. Do not move shared files blindly
For SharePoint and OneDrive, map owners, permissions, paths, oversized files and external shares. Structure collaboration around how people work rather than reproducing every file-server folder without review.
4. Cutover and DNS readiness
Review affected DNS records such as MX, Autodiscover and relevant email authentication entries. Define owners, acceptance criteria, user communications and a realistic maintenance window.
- Incoming and outgoing mail tests
- Delegation and calendar checks
- Mobile devices and external-sender checks
5. Accept the migration based on business workflows
Verify user scenarios rather than merely checking that a mailbox exists in the admin portal. Agree what completion means, how user issues are resolved and who owns ongoing operations.
VALUE360 plans Microsoft 365 migrations around assessment, pilot users, mail-flow tests and a documented handover.
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Technical references
Microsoft 365 environment review
Inventory Entra ID policies, user and application permissions, audit logs and exceptions. Pilot changes with a limited group, validate access impact and define a rollback path.
Implementation questions
Does this automatically affect our environment?
No. First verify whether the specific product, version and relevant configuration are deployed.
Is a security tool enough on its own?
No. Combine patching, restricted access, logging and tested backups.