A good migration starts before the cutover
A Microsoft 365 migration is not only an email move. For most small businesses, it touches user accounts, licensing, shared mailboxes, aliases, file access, mobile devices, security settings, backups, DNS records, and employee training. The smoother migrations are planned before the first mailbox is moved.
This checklist is built for small and medium businesses that want the benefits of Microsoft 365 without losing track of the operational details that keep employees working.
1. Inventory the current environment
- List users, mailboxes, aliases, and groups. Include shared mailboxes, distribution lists, resource calendars, and former employee accounts that may still receive mail.
- Identify critical data locations. Note what lives in Exchange, file servers, Google Workspace, local workstations, third-party apps, and shared drives.
- Document DNS and domain access. Confirm who controls DNS, registrar access, spam filtering, website DNS, and mail-routing records.
- Check devices and applications. Review Outlook versions, mobile devices, scanners, copiers, CRM tools, accounting software, and line-of-business apps that send mail.
2. Decide the right Microsoft 365 licensing and security baseline
Licensing affects security features, storage, device management, mailbox size, and future support options. The cheapest license is not always the best value if it creates extra administration or leaves needed controls unavailable.
- Match licenses to real roles. Owners, office staff, field users, shared devices, and contractors may need different licensing.
- Plan multifactor authentication. MFA should be enabled deliberately, with recovery options and admin accounts handled carefully.
- Review mailbox and file retention needs. Decide what must be preserved before deleting or merging old accounts.
3. Plan the cutover around employee impact
The migration window should account for business hours, leadership availability, employee schedules, device access, and how quickly support can respond after the move. A technically successful migration can still feel messy if users are surprised by profile changes, mobile prompts, missing shared access, or new sign-in requirements.
- Communicate what will change. Tell users when to expect password prompts, Outlook profile changes, mobile reconfiguration, or MFA setup.
- Schedule support coverage. Have help available when employees first open Outlook, Teams, OneDrive, or mobile mail after the move.
- Protect mail flow. Confirm DNS timing, MX records, SPF, DKIM, DMARC, and any spam-filtering changes.
4. Clean up permissions during the move
A migration is a good time to fix access problems that have grown quietly over the years. Shared mailboxes, calendars, file shares, former employee data, and global administrator roles should not simply be copied forward without review.
- Reduce stale access. Remove permissions that no longer match job roles or business needs.
- Standardize shared mailboxes and groups. Make ownership clear so future changes are easier to support.
- Limit administrator accounts. Use named accounts and document who can make tenant-wide changes.
5. Verify after migration
Post-migration verification is where small problems are caught before they turn into recurring tickets. Check mail flow, mobile devices, shared calendars, scanners, application mail, OneDrive sync, Teams access, backup status, and user permissions.