“The tools version '15.0' is unrecognized” #838

I am on Windows 7 x64 PC trying to open a 3rd party C# project file. As the project file needs BuildTools v15 to be installed on a machine I have installed it by downloading MS official small file internet installer.

But when I try to open a project created in Microsoft Visual Studio upon opening it gives me error:

"The tools version 15 is unrecognized. Available tools versions are 2.0, 3.0 and 4.0"

I guess it has something to do with the way BuildTools 2019 are installed cos the previous version 2015 (actually version 14) which has offline installer has been correctly recognized by SharpDevelop.

I read somewhere that it may help to uninstall any previous BuildTools versions (in my case it was just the previous one, that is BuildTools 2015) but it did not help - BuildTools 2019 is still unrecognized by SharpDevelop.

Is there a solution to this? Like setting the path to the actual BuildTools 2019 folder/.exe somewhere for the SharpDevelop?