I have also noticed this problem and the solution is to first install the MDS Excel plugin for SQL Server 2016 and after that run the 2017 installation. The 2017 will then upgrade the 2016 plugin to 2017.
I have also noticed this problem and the solution is to first install the MDS Excel plugin for SQL Server 2016 and after that run the 2017 installation. The 2017 will then upgrade the 2016 plugin to 2017.