This application requires one of the following versions of .NET Framework

We recently came across a similar problem. When starting a service, we received the error "This application requires one of the following versions of .NET Framework:"

We discovered the issue was our misunderstanding of how to update the app.config file.

We had changed the app.config file to set<supportedRuntime version="v4.7" sku=".NETFramework,Version=v4.7" />

But should have set it to <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7" />

We had incorrectly set the major version of .NET as explained in https://docs.microsoft.com/en-us/dotnet/framework/configure-apps/file-schema/startup/supportedruntime-element#version

In case someone else encounters this, I had a similar problem with a windows service that wouldn't start due to an allegedly missing version 4.6 of the .NET framework. In my case, due to copy and paste, the following had happened in the config file:

<supportedRuntime version="v4.0" sku=".NETFramework, Version = v4.6"/>

whereas the following works:

<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6"/>

So, the spaces are the culprit and must not be there! Why I don't know, because you'd expect the parser to be a little less picky, but ok...

I had this same error today with SourceTree after applying a new Windows Insider version, with the difference that SourceTree was requiring 4.7.1.

I found that the version number was correct as 4.0 but, based on @Skyler Nesheim's answer, I changed the other attribute, sku, from being
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.1" />to be
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />and that made it work.