If you try to Install .Net Framework 4.7.2 and get an error like you have to install KB2919355 Windows update first, You can try to install the below windows update first and reboot your system when the update is completed. It will take a few minutes to 1 hour or more as this includes a lot of updates.


Download Required Official Updates - https://download.microsoft.com/download/D/B/1/DB1F29FC-316D-481E-B435-1654BA185DCF/Windows8.1-KB2919355-x64.msu

After Installed all the updates, You will be asked to perform a server reboot. After rebooted, You can now start installing .net Framework 4.7.2 properly. After .Net installed, you may be asked to perform another reboot as well. 

.Net Framework Download Page - https://www.microsoft.com/net/download/dotnet-framework-runtime

Offline installer - https://support.microsoft.com/en-us/help/4054530/microsoft-net-framework-4-7-2-offline-installer-for-windows

Wish you all the best.