Visual Studio 2017: build tools for v142 cannot be found error, even though Platform Toolset is set to v141

Question

I'm building an openFrameworks project (using the project generator which generates VS2017 solutions) but am receiving the "build tools for v142 cannot be found" error. Answers across Stack Overflow say to go into Project > Properties > Configuration Properties > General and set Platform Toolset to v141 in order to downgrade, however my project fails to build with the same error even after doing this. See this screenshot for details:

Here's what I installed from the installer:

I do have VS 2019 installed as well, and I cannot uninstall it.

How can I resolve this error and build on VS 2017?

Answer 1

As @dxiv mentioned in the comments: "The error references one project, but the Property Pages refer to another." Every project in the solution (there should be two for OF projects, yourProjectName and openframeworksLib) needs to be individually downgraded. Instead of going to Project > Properties via the top toolbar, right click on each project in the Solution Explorer and get to the Properties menu for each of them from there.

And I just realized the top toolbar's Project menu item coincides with whatever item you currently have selected from the Solution explorer.