German Umlaute get corrupted on macOS Sierra

[Tiemo Hollmann TB]

Hello,

 

Today a customer with a Mac book Air and macOS Sierra called me and told me
that all German Umlaute in my LC 6 program are corrupted (while they are
working fine in all other programs). This is in text displayed in fields as
well as text entered in fields.

Since I don't have Sierra yet installed on my machine, I can't reproduce, if
this is a general Sierra issue, or something special on that customer
machine. Since this is the first customer telling me this problem I don't
even know, if no other customer has installed Sierra yet and it's a LC 6 -
Sierra issue or if others already have installed Sierra and don't see this
issue. 

 

I checked with this customer all language and keyboard layout settings and
they are all standard German, like on my 10.11 machine.

Has anybody any idea what could cause such a phenomenon? Any idea what to
look for? Or is LC 6 just incompatible with Sierra?

Thanks

Tiemo