I never thought I'd get this (in their words) "hack" from a supply chain consultant, but apparently anything is possible in 2020. Here is a great way to run multiple desktop Teams clients at the same time.
Copy and paste the following into a text editor:
@ECHO OFF REM Uses the file name as the profile name SET MSTEAMS_PROFILE=%~n0 ECHO - Using profile "%MSTEAMS_PROFILE%" SET "OLD_USERPROFILE=%USERPROFILE%" SET "USERPROFILE=%LOCALAPPDATA%\Microsoft\Teams\CustomProfiles\%MSTEAMS_PROFILE%" ECHO - Launching MS Teams with profile %MSTEAMS_PROFILE% cd "%OLD_USERPROFILE%\AppData\Local\Microsoft\Teams" "%OLD_USERPROFILE%\AppData\Local\Microsoft\Teams\Update.exe" --processStart "Teams.exe"
Name the file whatever you want, and give it a .cmd extension.
Now with a mere double click, I can have two desktop Teams clients open, at the same time. In this example, I have my work account open and a guest account open for a customer: