Register the new Teams as the chat app for Microsoft 365(requires restarting Microsoft 365 applications) is not working

In our environment, some registries were missing the key in HKEY_LOCAL_MACHINE\SOFTWARE\IM Providers\MsTeams

So FYI to everyone, the registry key location might be different in your environment. I just compared registry keys like John did and exported imported.

This has worked for me.!!! Thanks @John P Fitzgerald ..

Others can also try..

Any update of this New Teams issue?

or can please share some reg to edit to resolve this?

We experienced a similar issue in which users did not have the ability to "Register Teams...". The root cause was a GPO that had set a "deny" permission for Users on the HKCU:\SOFTWARE\IM Providers\ key. This was originally put into place when the classic Teams was first introduced in our school. At the time, we were also using Cisco Jabber. Jabber and Teams kept "competing" for the DefautIM/"Outlook presence" role. Whichever application was launched last, was designated as the DefaultIM and therefore the Outlook "presence" app. So we had implemented the Deny permissions along with setting the DefaultIM to Teams via a GPO.

When we went to the New Teams, we had to update the GPO to use "MsTeams" as the DefaultIM. However, if we removed the "Deny" permissions we would still experience Jabber and New Teams competing as it would automatically adjust the DefaultIM based on most recent app launched.

Another options for us was to remove Jabber and reinstall using the following which will remove the disable the Office integration in Jabber and therefore remove this issue. msiexec.exe CLEAR=1 /i CiscoJabberSetup.msi CLICK2X=DISABLE. After this was done, we are able to remove the "Deny" permissions and allow the users to check the "Register teams" checkbox.

Hope this helps.