How Are You Handling Office 365 Migrations? Sharing My Experience

Dear Folks,

Recently completed an Office 365 migration for a mid-sized org and wanted to share some observations and get a discussion going.

Scope covered:

• User mailboxes
• Shared mailboxes
• Archive mailboxes
• Public folders

Overall it went reasonably well, but we hit a few friction points — particularly around public folder cutover timing and ensuring archive mailbox permissions carried over cleanly. Mailbox structure and data consistency held up after the move, but it required careful pre-migration validation.

Would love to hear how others approach this:

Do you prefer staged or cutover migrations, and what drives that decision for you?

Any strategies for handling large mailboxes (50GB+) without running into throttling?

How do you manage the coexistence window and MX record cutover to minimize user disruption?

Happy to share more specifics if useful.