- Edited
Ok thats weird: The issue occured due to the german translation package.I have uploaded the de.phar in the include/i18n folder and was able to select german as the system language.I did the installation again without uploading the additional language and finished the installer with english and now everything is fine.However, when I upload the language file now and select it under settings / system / primary language it is ignored. My installation is english now and I'm unable to switch to german.But this is another topic.