New Teams is not prefilling UPN upon first start

Copper Contributor

As per my comment on the blog post I'm hoping someone can assist with a changed behaviour on the New Teams. We have domain-joined Windows 10 computers with Azure Active Directory configured to use pass-through authentication. We deployed the Classic Teams using the Teams_windows_x64.msi package with the argument



Following deployment when a user first started Teams, their UPN was pre-filled, so all they had to do type was their password:

Classic Teams sign-inClassic Teams sign-in

This doesn't happen when we deploy the New Teams. We deploy this following Option 1B using:

.\teamsbootstrapper.exe -p -o "\unc\path\to\teams.msix"

When a user starts New Teams for the first time, they are required to enter their UPN:

New Teams sign-inNew Teams sign-in


We'd like the old behaviour! Can anyone assist?

2 Replies
I have the same problem but no solution yet :(

@Paul-Christiaan Dikswe are working around this by deploying both the Classic Teams with autostart set and New Teams, and setting a Teams Update Policy of either Microsoft Controlled or New Teams Default. When the user first signs-in:

  1. Teams Classic starts and autofills their UPN
  2. After the user enters their password, Classic Teams starts, and immediately tells the user the next time they start Teams, New Teams will take effect.
  3. When New Teams starts their UPN is autofilled as Teams Classic took care of that.

In summary, we're using the autostart functionality of Classic Teams to bootstrap authentication for New Teams.


It's a hacky workaround but it seems to do the job. Judging by the below rather confusing Teams migration graphic Microsoft have released, it seems they will support this "just install both and let Teams migrate from Classic to New" approach as there's an extensive period from mid-May to end of June there where the Classic Teams installer remains available despite New Teams Only being the only operating paradigm. Hopefully they figure out this mess by then.