Forum Discussion
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.
1 Reply
Thanks for sharing this — public folder cutover timing is genuinely one of the trickier parts of any Office 365 migration, so good to hear it held up overall.
To answer your questions based on my experience:
Staged vs Cutover: For mid-sized orgs, staged migration almost always makes more sense. Cutover works cleanly only when you have a small number of mailboxes and a tight migration window. Once you're dealing with archive mailboxes and shared mailboxes in the mix, staged gives you much better control over validation at each step.
Large Mailboxes (50GB+): Throttling is a real pain here. Breaking migrations into off-peak batches and prioritizing active users first helps significantly. Also, migrating archive mailboxes separately from primary mailboxes reduces the load considerably.
Coexistence & MX Cutover: Keeping the coexistence window as short as practically possible reduces confusion for end users. Running a pilot group first and validating mail flow thoroughly before flipping MX records has saved a lot of headaches.
On the tooling side, we've had good results using EdbMails Office 365 Migration. It handles bulk mailbox migrations well, supports incremental migration to keep data in sync during coexistence, and the selective folder migration feature is handy when dealing with oversized mailboxes. The free trial also lets you test with up to 30 items per folder before committing, which is useful for pre-migration validation.
