Shared inboxes hold years of institutional memory, which is exactly what makes leaving them feel risky. This runbook breaks the move into four weeks of concrete tasks with explicit exit criteria, and includes the rollback plan most migrations skip.
Week one, audit
Inventory every address and channel receiving customer messages, including the founder's personal address and the dormant social page. Record volume, unique senders and median response time per source. Retire the long tail before you migrate it; importing dead addresses adds risk for no benefit.
Week two, decide what history moves
Import the last 12 to 18 months mapped to customer records, keep everything older in a searchable archive, and exclude automated notifications and internal chatter entirely. Agree identity-mapping rules now, because the import will surface every duplicate customer record you have.
Week three, parallel running
Forward inbound mail to the new platform while the legacy inbox stays receiving but read-only. Agents work exclusively in the new system. The hard rule is that no reply leaves the old inbox, because a single out-of-band reply creates a thread the new platform cannot see.
Week four, cutover
- Change forwarding or MX records during a low-volume window with a named owner on call.
- Move remaining open conversations by hand, there are usually fewer than fifty.
- Watch four numbers daily for two weeks: unassigned count, oldest unanswered conversation, response-time distribution, and replies still leaving the legacy system.
- Publish the new internal expectations, including where personal-address replies are no longer acceptable.
The rollback
Rollback is a forwarding change plus an internal message, and it belongs in writing before cutover with a named decision owner and a numeric trigger. Teams without one tend to endure a bad week instead of reverting cleanly and trying again.