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Consultant-focused KB for Microsoft Teams: implementation notes, gotchas and configuration decisions beyond the official docs — across chat and collaboration, meetings, webinars and town halls, Teams Phone, PSTN connectivity (Direct Routing, Operator Connect, Calling Plans, Teams Phone Mobile), auto attendants, call queues and contact centre integration, Teams Rooms and devices, apps and extensibility, Copilot in Teams, administration and governance, security and compliance, network and call quality, and licensing — plus cross-cutting decision guides.

teams/01-chat-and-collaboration/feature-new-teams-client-multi-account.md
feature-new-teams-client-multi-account.mdv1 · history
CurrentApplies to AllUpdated 3 weeks agoSource Microsoft Learn ↗

What it does

The only Teams desktop client now: an MSIX-packaged app built on WebView2 that replaced classic Teams. It runs multiple work, school and personal accounts side by side, so people who work across organisations stop switching tenants.

Key facts

  • Classic Teams reached end of availability on 1 July 2025 for native clients, VDI, GCC, GCCH and DoD. End of support was 1 July 2024 for native clients and 1 October 2024 for VDI and the US government clouds. Users left on classic were pointed to the web app or their IT team.
  • Bulk deployment uses teamsbootstrapper.exe -p, which provisions the MSIX package for every user on the machine and any user added later, replacing other Teams versions already installed. -o points at an offline MSIX (local or UNC), --installTMA installs the Teams Meeting Add-in, and -x uninstalls. MSIX packages exist for x64, x86 and ARM64.
  • Always use the latest bootstrapper — Microsoft says to check Properties > Details > Product version.
  • Prerequisites: Microsoft 365 Apps or Office LTSC 2021, current WebView2, Delivery Optimization (Download Mode 100 Bypass isn't supported), and "Show Notification Banners" enabled for Teams in Windows notifications.
  • Windows minimum is 10.0.19041; LTSC builds of Windows aren't supported. 4 GB RAM and 3 GB free disk on Windows; macOS needs one of the three most recent macOS versions.
  • The client updates itself in the background. An in-app alert shows when the installed version is one to three months old; on VDI, 60+ days gives alerts and 90+ days blocks.
  • Multiple accounts and organisations are supported when they're in the same Microsoft 365 cloud environment. Cross-cloud guest access and cross-cloud meetings aren't.
  • Government cloud installs are steered with the CloudType DWORD under HKCU\SOFTWARE\Policies\Microsoft\Office\16.0\Teams (1 commercial, 2 GCC, 3 GCCH, 4 DoD, 7 Gallatin), or com.microsoft.teams2 on macOS.
  • On VDI, WebRTC-based optimisation reaches end of support on 1 October 2026 for Windows endpoints and end of availability on 1 April 2027, with the SlimCore-based optimisation replacing it.
  • The desktop client is no longer supported on Linux; Linux users run Teams on the web or as a PWA.

When to use / skip

There's no "skip" any more — classic is gone. The real work on current projects is cleaning up after a migration that was done in a hurry: machines still carrying classic remnants, the meeting add-in missing from Outlook, VDI images built before the bootstrapper settled down, and multi-account behaviour nobody explained to users.

The multi-account side is where you add value. Consultants, partners, and anyone in a multi-tenant organisation can add their other work accounts and guest tenants and get notifications from all of them without switching. That changes the guest-vs-shared-channel conversation too: with multiple accounts in the client, guest access is far less painful than it used to be.

Configuration decisions

  • Deployment method: bootstrapper with online install, bootstrapper with an offline MSIX on a share, or Intune/Configuration Manager wrapping the bootstrapper.
  • Whether Delivery Optimization is permitted on the network — it's a hard dependency for updates, and some security teams block it.
  • VDI approach: persistent vs non-persistent, profile roaming for the MSTeams package folders (FSLogix with Teams included), and whether to disable auto-update with disableAutoUpdate on non-persistent images.
  • Timing the move from WebRTC to SlimCore-based VDI optimisation before the October 2026 / April 2027 dates.
  • Whether users should add personal accounts to the corporate client, and how that sits with acceptable use policy.
  • How to clean up classic Teams leftovers and per-user installs on shared machines.

Gotchas

  • Delivery Optimization in Bypass mode silently breaks updates. Users drift past three months old and start getting alerts.
  • Disabling auto-update on VDI also stops the Teams Meeting Add-in being installed automatically — use --installTMA.
  • Users who uninstalled classic Teams by hand often lost the Outlook meeting add-in. Reinstall it rather than reinstalling Teams.
  • Antivirus and DLP tools that hook into new processes can stop the MSIX launching. Add the exclusions Microsoft lists before blaming the package.
  • Multi-account doesn't cross clouds. A commercial user can't add a GCC account and expect it to behave.
  • Old VDI images built before the relevant Windows cumulative updates hit known launch and registration failures. Patch the image first.

Consultant notes

  • Keep a one-page "current client" baseline for each client: bootstrapper version, MSIX source, DO mode, VDI optimisation in use.
  • On any VDI estate, put the WebRTC end-of-support date in front of the client now — it's this month.
  • Show users the add-account option in a five-minute session. It removes a surprising amount of guest-access friction.
  • Update policies and client rollout governance belong with the administration workstream; this doc stops at the client itself.
  • When something looks broken, try the web client first. If the web client works, it's local — WebView2, profile, AV, or DO.

Revisit after the VDI WebRTC end-of-availability date in April 2027, or if Microsoft lifts the same-cloud limit on multiple accounts

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