The error message for when trying to create existing users/groups is incomplete in the German (Germany) translation.
It does not signify users in the error message as does the English translation.

Correct:
English (United States):
"A group or user with this name already exists."

German (Switzerland)

• "Eine Gruppe oder ein Benutzer mit diesem Namen ist bereits vorhanden"
• becomes: "A group or a user with that name already exists"

Incorrect:
German (Germany)

• "Eine Benutzergruppe mit diesem Namen existiert bereits"
• becomes: "A user group with that name already exists"