Option 1: Enable Teams Chat by wave, along with the migration of personal data
Option 2: Enable Teams Chat for all employees from the start of the migration
Migrated users get full Teams functionality (chat, calls, meetings, files, calendar).
Non-migrated users stay entirely on Google. Chat/Meet until their migration. Reduced confusion around calendars and file storage: Users aren’t exposed to non-functional icons (Calendar, Files, OneDrive).
Users in different GBUs cannot chat or call across Microsoft Teams and must continue to rely on Google Chat for cross-BU communication.
Coexistence must be clearly communicated on especially the way to check if a user is migrated or not.
Risk of confusion or missed messages between migrated and non-migrated users.
All users (migrated or not) can chat and call immediately. Reduces “who’s where” confusion; everyone appears reachable on the same platform. Eases early adoption via early exposure to Teams for all users supports training and adoption campaigns.
Non-migrated users will see “Files,” “OneDrive,” and “Teams” tabs but not all are functional until their wave migrates, which may create confusion.
Mixed UX for file sharing: migrated users can upload files directly in the Teams chat, non-migrated users can't (only share Google Drive URLs)
Calendar de-sync: For non-migrated users (still on Gmail), Teams calendar will be disabled and Teams meeting cannot be sheduled until migrated.
Fewer “why doesn’t this work” tickets.
Support can focus on the migrated BU instead of the entire company.
Training and communications can be targeted and timed per BU.
Simplifies rollout communications on impacts/coexistence AND enables a single company-wide communication channel (Teams)
Potential tickets from non-migrated users "“Why can’t I upload from my desktop?” and "Why is my Calendar empty / not working"?
Support desk must handle two user populations: Users with full functionality (migrated), Users with limited functionality (chat/call only).
Teams’ adoption staggered — organization doesn’t reach the “network effect” of full collaboration until the last BU migrates. Teams can be used for multi-GBU projects or transversal initiatives. Partly mitigates the chat history not being migrated as all users can be redirected to Teams from day 1. Teams’ usage metrics will look inconsistent: many users enabled but only partially active until migration completes.