Run multiple Teams Desktop applications in Windows

MyProfileName.ps1

$profileName = [io.path]::GetFileNameWithoutExtension($PSCommandPath)
Write-Output "Launching $profileName Teams Profile ..."

$userProfile = $env:USERPROFILE
$appDataPath = $env:LOCALAPPDATA
$customProfile = "$appDataPath\Microsoft\Teams\CustomProfiles\$profileName"
$downloadPath = Join-Path $customProfile "Downloads"

if (!(Test-Path -PathType Container $downloadPath)) {
  New-Item $downloadPath -ItemType Directory |
    Select-Object -ExpandProperty FullName
}

$env:USERPROFILE = $customProfile
Start-Process `
  -FilePath "$appDataPath\Microsoft\Teams\Update.exe" `
  -ArgumentList '--processStart "Teams.exe"' `
  -WorkingDirectory "$appDataPath\Microsoft\Teams"

Note, don't reuse the shell after running this code because it changes environment variables, which will make other applications, like VS Code, try to create new profiles as well.