I needed to install .NET 4.7.1 to allow updating Exchange 2013 to CU 21.
This is the installer I downloaded and tried to install: https://www.microsoft.com/en-us/download/details.aspx?id=56116
But the installation never ends. It remains stuck without progressing in the “Installation progress” bar. Tested both with offline and online installation:
To install .NET Framework 4.7.1 download the msu package from the following link:
https://www.catalog.update.microsoft.com/Search.aspx?q=KB4033369
It seems that there is some kind of problem with the other format, but the msu worked correctly for me.
Thanks so much for posting this. Ran into the same issue when installing CU10 for Exchange 2016. For anyone looking for the msu of .NET 4.7.1 for Windows Server 2016 here it is: https://www.catalog.update.microsoft.com/Search.aspx?q=KB4033393
Thank you! worked for me for 4.7.2