Hallo,
ich habe das gleiche Problem und ich glaube es liegt nicht an uns 
Mein Post ist hier: Zwift launcher causes script error on Windows 10
English version:
I posted the same behaviour here yesterday: Zwift launcher causes script error on Windows 10
I verified that it also occurs on a complete new Win10 installation (1909) with just Zwift installed.
The behaviour is not noticeable when you are always logged in with the same user. But as soon as you switch users, the script error occurs.
Anyone any idea? Thanks.
Frank