Migrating to Microsoft 365 without interrupting your business

Moving to Microsoft 365 makes many business owners hesitate: what if the emails stopped on a Monday morning? Properly prepared, a migration nevertheless runs with no visible interruption for your teams. Here is the method we recommend, in four steps.

Why migrate?

Microsoft 365 brings together email (Exchange Online), file storage and sharing (OneDrive, SharePoint), video conferencing and collaboration (Teams), all accessible from anywhere and updated automatically. Depending on the plan you choose (Business Basic, Standard or Premium), you also get the installed Office apps and advanced security features. For an SME, it means no longer managing an ageing mail server.

What really causes an interruption

Outages almost never come from Microsoft, but from insufficient preparation: an email cutover done in the middle of the day, forgotten mailboxes, a printer or software still sending mail with the old configuration, passwords not handed out. All of this can be planned for.

Step 1: audit and preparation

We start with an inventory: mailboxes and their size, aliases, shared mailboxes, distribution lists, devices (computers, smartphones), and above all the applications that send emails (scanners, invoicing software…). We choose the right licences and check your domain configuration (DNS records, SPF, DKIM, DMARC).

Step 2: gradual migration in the background

Mailboxes are copied to Microsoft 365 while your teams carry on working normally on the old system. We begin with a pilot involving one or two users to validate the method, and lower the DNS propagation time (TTL) beforehand so the cutover is fast.

Step 3: the cutover

It takes place outside office hours, usually in the evening or at the weekend: we redirect the email flow to Microsoft 365, check sending and receiving, then a final synchronisation retrieves the messages that arrived on the old system during the transition. Workstations are then configured so everyone finds their mailbox on Monday morning.

Step 4: secure and support

• enable multi-factor authentication for all accounts — the most effective protection against stolen credentials, see our article on phishing;
• plan an independent backup of your Microsoft 365 data: responsibility for the data remains with the company;
• train teams quickly on the new tools (a short session is often enough);
• provide reinforced support during the first days.

Your checklist before you start

• List of all mailboxes, aliases and shared mailboxes
• Applications and devices that send emails
• Access to your domain name (DNS) management
• Cutover date chosen outside working hours
• Communication and training plan for the team

At Gigaweb, we support SMEs end to end: audit, migration, security and support, with our collaboration tools and our expertise in IT infrastructure.