Microsoft 365 migration checklist for businesses
What IT managers and business owners should inventory before moving company email and files from cPanel, IMAP or Google Workspace to Microsoft 365.
- Audit every active mailbox, shared address, alias and forwarder before purchasing licenses.
- Locate local Outlook PST archives stored on individual employee laptops.
- Lower DNS TTL values 48 hours prior to scheduled MX cutover.
- Configure SPF, DKIM and DMARC immediately to protect domain deliverability.
1. Domain, DNS & Sender Inventory
Before touching a single mailbox, confirm who holds registrar access to your domain name and where the active DNS zone is hosted. List every system that sends email using your domain—including ERP systems, multifunction office scanners and website contact forms—so their SMTP relays do not break on cutover day.
2. Mailbox & Local Archive Discovery
If your company previously used POP3 or small webmail quotas, critical historical emails may reside only inside local .PST files on employee laptops rather than on the mail server. A proper migration plan captures both server-side folders and local archives.
3. Pre-Staging & Cutover Execution
Never wait until cutover day to copy gigabytes of historical mail. Sync 95% of historical data in the background days in advance, validate item counts, switch MX records during a quiet window, and run a final delta pass.