Changing a Company’s domain touches everything: every user account, every group, every signature, every integration that checks a login against an email address. Get one part wrong and people show up to a broken inbox, or worse, one that looks fine and quietly drops mail. This client needed the switch done overnight, with the whole team back online and working normally by the time the office opened.
The plan
We moved every user’s primary email address from the old domain to the new one in a single overnight window. The old domain stayed live as an alias, so nothing sent to the previous address bounced, and nobody had to update contacts or resend anything. Staff logged in the next morning with their existing password and saw no change to how Gmail worked day to day.
Staff members were informed beforehand so they knew that when they came in that morning they would have a new email, with everything from their old inbox exactly where it should be.
The fault testing caught
We never migrate everyone in one pass and hope. Before the overnight cutover, we ran the move on a small test group and watched how mail behaved. That test proved useful.
The test department’s email group stopped delivering. Messages sent to the group address showed up in the Google Groups web interface, but members never received them in their inbox. Nothing bounced, and nothing looked broken from the admin console.
We worked through the usual suspects first: group access permissions, moderation settings, membership records, DNS routing. Each one checked out. The actual cause sat one level down, in each member’s individual delivery preference for that specific group, which had reset during the account changes without any error or warning.
Once we found it, the fix took minutes. Finding it took methodically ruling out everything else, because a partial mail failure like this gives almost no signal about where it’s going wrong. We corrected the setting, confirmed mail flowed, and built the same fix into the plan for the full migration.
The result
Because testing caught the group fault first, the overnight migration ran clean. Every user was up and working the next morning, with no lost mail and no support calls about login problems. The one problem that could have silenced an inbox for weeks was found and fixed before it reached the wider team.
Planning a domain or email migration? The parts that go wrong are rarely the parts anyone expects. Get in touch and we’ll plan it properly before you touch anything.