Alternate viewer won't install. You get a .NET Framework error.
a) Press “Windows Logo” + “R” keys on the keyboard.
b) Type “appwiz.cpl” in the “Run” command box and press “ENTER”.
c) In the “Programs and Features” window, click on the link “Turn Windows features on or off”.
d) Check if the “.NET Framework 3.5 (includes .NET 2.0 and 3.0)” option is available in it.
e) If yes, then enable it and then click on “OK”.
f) Follow the on-screen instructions to complete the installation and restart the computer, if prompted.
g)Try the setup again
You can also use the following command from an Administrator command prompt to install the feature:
DISM /Online /Enable-Feature /FeatureName:NetFx3 /All
Windows 10 does not have .NET Framework 3.5 installed by default. The alternate viewer is dependent on this.