Opening https://teams.microsoft.com directly in the desktop Electron preview can route to the retired Classic Teams page instead of the current Teams sign-in flow. There is currently no per-profile User-Agent setting to try a compatible identity for that site.
This report concerns entering Teams Web, not opening a meeting link. The original user report also described a desktop-app handoff. The isolated reproduction below established the Classic Teams error; it did not reproduce an external-protocol launch.
Reproduction and environment
- macOS arm64, T3 Code Nightly
0.0.46-nightly.20261005.2689.
- Electron
44.4.2, Chromium 152.0.7977.130.
- Fresh Electron browser storage, no credentials entered.
- Open
https://teams.microsoft.com with the native T3/Electron User-Agent.
- Observed destination:
https://teams.microsoft.com/error/eoa, with “Classic Teams is no longer available”.
- Repeat with the same engine and platform, removing only the app/Electron tokens from the User-Agent.
- Observed destination: the Microsoft sign-in form at
login.microsoftonline.com. An authenticated Teams session was not tested.
Expected behavior
Allow a custom desktop browser profile to choose an opt-in Chrome-compatible User-Agent for sites that misidentify Electron. Preserve the exact native default, including built-in profiles, and allow returning to Native. Apply a changed setting to newly opened/reopened tabs while retaining the profile's cookies.
The native default is intentional: #5002 and #7110 describe Turnstile failures caused by a global User-Agent rewrite. This report does not propose changing that default or replacing Electron with another browser engine. It also does not establish that a User-Agent override resolves embedded-browser sign-in policies such as #14815.
Prepared with GPT-6.1-Sol using Codex in T3 Code.
Opening
https://teams.microsoft.comdirectly in the desktop Electron preview can route to the retired Classic Teams page instead of the current Teams sign-in flow. There is currently no per-profile User-Agent setting to try a compatible identity for that site.This report concerns entering Teams Web, not opening a meeting link. The original user report also described a desktop-app handoff. The isolated reproduction below established the Classic Teams error; it did not reproduce an external-protocol launch.
Reproduction and environment
0.0.46-nightly.20261005.2689.44.4.2, Chromium152.0.7977.130.https://teams.microsoft.comwith the native T3/Electron User-Agent.https://teams.microsoft.com/error/eoa, with “Classic Teams is no longer available”.login.microsoftonline.com. An authenticated Teams session was not tested.Expected behavior
Allow a custom desktop browser profile to choose an opt-in Chrome-compatible User-Agent for sites that misidentify Electron. Preserve the exact native default, including built-in profiles, and allow returning to Native. Apply a changed setting to newly opened/reopened tabs while retaining the profile's cookies.
The native default is intentional: #5002 and #7110 describe Turnstile failures caused by a global User-Agent rewrite. This report does not propose changing that default or replacing Electron with another browser engine. It also does not establish that a User-Agent override resolves embedded-browser sign-in policies such as #14815.
Prepared with GPT-6.1-Sol using Codex in T3 Code.