🩺 FixMyMeeting

How to enable the developer tools in Teams

New Teams for Windows has a hidden menu called “Engineering Tools”. Its entry “Open Dev Tools” opens the browser developer tools inside Teams. With them you can capture and inspect the web requests of Teams itself, without installing a separate tool such as Fiddler.

This guide is for IT professionals. The menu is hidden on purpose and meant for troubleshooting. What you see can differ between Teams versions and company policies.

Turn on the Engineering Tools (Windows)

  1. Quit Teams completely: right-click the Teams icon in the taskbar notification area (click the small arrow ^ if you do not see it) › Quit.
  2. Press the Windows key + R, paste this path and press Enter: %localappdata%\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams
  3. In this folder, create a new text file and name it configuration.json. To make sure it does not end up as configuration.json.txt, first turn on File Explorer › View › Show › File name extensions.
  4. Open the file in Notepad, paste the following line and save the file: {"core/devMenuEnabled": true}
  5. Start Teams again.
  6. Right-click the Teams icon in the notification area. The menu now contains the entry “Engineering Tools”.

Capture web requests with Dev Tools

  1. Right-click the Teams icon in the notification area › Engineering Tools › Open Dev Tools. A window with the browser developer tools opens.
  2. Open the “Network” tab and turn on “Preserve log”, so the entries stay when Teams reloads a view.
  3. Reproduce the problem in Teams, for example open the chat that does not load.
  4. Click a request in the list to see its address, status code, timing, headers and response. Use the filter box to find the request you are looking for. Requests with a status of 4xx or 5xx failed.
  5. To share a capture, export it as a HAR file: right-click in the request list › “Save all as HAR with content”.

Handle captures with care

  1. A capture can contain sign-in tokens, cookies and message content. Share a HAR file only with people who need it, and remove or revoke secrets first.
  2. Use this only on computers you are responsible for, and follow your organisation’s rules for troubleshooting tools.

Turn it off again

  1. Quit Teams.
  2. Delete configuration.json, or change the value to false.
  3. Start Teams again. The entry “Engineering Tools” is gone.

Good to know

  1. These steps are for new Teams on Windows. The classic Teams app is no longer supported by Microsoft.
  2. If the folder does not exist, start new Teams once and sign in; Teams then creates its data folder.
  3. Menu entries can change between Teams versions.

Chats or channels that do not load? Capture the requests while the problem happens and look for failed requests.