I've developed an Arduino app using VS2019 and vMicro on my laptop 9 months ago.  I just went back to this and now have spent quite a few hours trying to fix an apparently mangled install.  After trying many things and uninstalling / reinstalling both Arduino IDE and vMicro, I cannot build the previous project/sketch that I had been working on in vMicro.  I can build it in Arduino 2.3.6 IDE. I created a new Arduino project, added two lines of code and attempted to build, but get the error "cannot open.. arduino.h". I look at 'Configure IDE Location and it shows Arduino 1.6/1.8 selected. I had uninstalled Arduino entirely and installed 2.3.6. I changed the dropdown to point to Arduino 2 and select Rescan Toolchain. I get the error 'object reference not set.. Ide=Arduino 2', and the IDE selection has been set back to 1.6/1.8. Any help would be greatly appreciated. I have attached the build log

verbose build log

Thanks for the details, would it be possible to email us the "test" project as a ZIP (delete the *.vs folder before compressing)?

To rollback you will need to Uninstall Visual Micro: 
https://www.visualmicro.com/page/Uninstalling-Visual-Micro.aspx

Then download the previous release from our Downloads Page, and install that using the Visual Studio Version Selector (noted at the bottom of the Downloads Page):
https://www.visualmicro.com/page/Arduino-Visual-Studio-Downloads.aspx

If you have any issues downgrading let us know which version is currently shown in Extensions > Manage Extensions > Installed for Visual Micro.

I got an email bounceback so apparently typed wrong.  Here is the zip file