Visual Studio Solution Unavailable (reload doesn't work)

Question

I am downloading a sample program for a barcode reader that I am using. Everytime I download the program and run it I am prompted with the error in my solution explorer (see ima

Answer 1

I remove project by right click on the project and click remove. Then right click on the solution and add existing project you removed. If this didn't work then before adding the existing project delete csproj.user file and then add.