Hi @suppenkoch, sorry to hear about your issues.
It’s certainly rather strange that there remains artefacts after installing following the advice as given out in the above link and stranger still that the issue is not reproduced on your other system.
RS5 has not yet been comprehensively tested, so I will check with developers but in the meantime have you tried using an Uninstaller Software (eg. IOBit Uninstaller) that could monitor and hopefully uninstall all traces? Please try it out and let me know how you get on.
Thanks for your patience whilst we try to find a resolution to this issue.