If you resize your MSTSC window, and it won't restore to full screen, then use the following


Blurry Fonts on Windows 10

1) Right click on the application you want to correct the fonts of, select Properties
2) Go to Compatibility tab.
3) Under Settings section, check Disable display scaling on high DPI settings
4) Apply and close the window.

If using standard GUI installer does not work. Mount W2012R2 iso and use below command line:

Install-WindowsFeature –name NET-Framework-Core –source D:\sources\sxs