Microsoft 365 migration: succeed without disruption (and no surprises)

Switch to Microsoft 365 offers modern collaboration, enhanced security, and mobility. But a poorly planned migration can break email and productivity. Here is our method hassle-free.

1) Discovery & scoping

• Inventory of domains, mailboxes, shares, existing licenses
• DNS mapping (MX, autodiscover), email clients and mobile devices
• Risks: large mailboxes, forgotten aliases, BYOD devices

2) Migration plan

• Strategy : cutover (all at once) or staged (gradual)
• Windows/Outlook: autodiscover and profiles
• Governance: MFA, password policies, basic DLP
• Backup M365 (SharePoint/OneDrive/Exchange) — essential

3) Pre-copy & testing

• Pre-synchronize emails to minimize the switchover window
• Pilot accounts: validate send/receive, calendar, mobile devices

4) Switchover without interruption

• Switch the MX at the scheduled time
• User support (step by step for mobile devices and Outlook)
• Live monitoring of mail queues

5) Post-migration & security

• Enable MFA, policies Conditional Access
• Apply antiphishing and Safe Links
• Train the team: phishing, sharing, Teams

Common mistakes to avoid

• Forgetting the DNS records secondary
• No M365 backup (granular recovery)
• No MFA on day 1
• Underestimatingadoption (changes in habits)