Intro

Companies are now switching to new Teams, they have no choice unless they are running on VDI, so, if they have never tried it, or hold it until the last minute, they are doing it now, so, some issues are starting to show up, in this blog post, I’ll describe an issue that happened on one of my customers and how you can fix it.

The error

When you try to switch the Try the new Teams toggle, you will get the following red banner:

Investigation

If you open your logs.txt in %appdata%\Microsoft\Teams you will find something similar to this

event -- eventpdclevel: 1, resultCode: 3, transactionId: 678d39ed-9ad8-40f6-b5a8-164b690a80a8, apiName: undefined, message: Launch api returns false, code: 11, apiCode: undefined, extendedErrorCode: 0, launchStatus: failed, isRegKeyIssue: false, cookieRegKeyValue: %USERPROFILE%\AppData\Local\Microsoft\Windows\INetCookies, isAppDataIssue: false, appDataFilePath: , status: failure, scenario: 6f5c29fa-3f2b-4314-9801-09f1a0bbfb2b, scenarioName: launch_pear_app, name: launch_pear_app, step: stop, sequence: 3, delta: 8584, scenarioDelta: 8584, elapsed: 227965, stepDelta: 8538, Scenario.Mode: 1

if you are used to read this log file, scenarios are fired up by Teams apparently on every action performed by the user and launch_pear_app seems to be the one when launching New Teams.

I kept thinking about this line:

cookieRegKeyValue: %USERPROFILE%\AppData\Local\Microsoft\Windows\INetCookies

Doing some research, I found this article Applications try to access web cache content that belongs to the local Administrator account that talks about some issues when applications that use browser modules try to access files that belong to a computer’s Administrator profile in addition to files that belong to the current user’s profile, especially when, some imaging or deployment tools copy some or all of the Administrator profile content to the default user profile.

More detailed information in that article follows.

I was able to reproduce on a lab VM by removing permissions to the INETCookies folder to the user and boom! same error in the Teams user interface and the Teams logs.txt file.

Resolution

Follow the procedures described in the resolution section Applications try to access web cache content that belongs to the local Administrator account

Later I found that that this same error can also be caused by WindowsApps messed up folder permissions, and I found a great script to fix them to the defaults, go here if you want to grab it and give it a try Windows Apps Unuffuker.