I just had the same problem. Visual Studio isn’t building the project that’s being referenced.

Written Instructions:

  1. Right click on the solution and click Properties.
  2. Click Configuration on the left.
  3. Make sure the check box under “Build” for the project it can’t find is checked. If it is already checked, uncheck, hit apply and check the boxes again.
  4. (Optional) You had to do it for both Release and Debug modes on the solution properties.

Screen capture Instructions:

  • They say a picture is worth a thousand words. Click on the GIF to zoom in, and hopefully it will be easy to follow:

Gif Instructions