Official list of all targeting packs: https://www.microsoft.com/net/targeting. Make sure you download the "developer pack", not "runtime".
Direct links to offline installers: 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2
This problem seems to affect Visual Studio 2013 and Visual Studio 2015. The targeting packs are included in Visual Studio 2017.
Outdated links:
How I found that link
First, choose option 1, "Change the target to .NET Framework 4.5"
Next, go to the project options of the affected project, select "Application" and then choose "Install other frameworks..." from the list of target frameworks:
This brings you to a website where you can choose your version of Visual Studio and download the targeting pack (called developer pack).
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…