My perception is that, at some point in their careers, all great programmers travel through the fires of DLL Hell. It's a no man's land filled with billable hours and nothing to show for it. Many have died along the way. When I experienced the slew of errors shown below, I too thought I was in for the fiery test. The fix, as it turned out, was pretty easy.
The issue is that the dlls do exist locally, but there is a mismatch of sorts and Nuget can't find them. The easiest fix is the following:
- Close the solution in Visual Studio
- Open a Windows Explorer window.
- Navigate to the packages folder on your computer. It'll be on the same level as the solution file.
- Delete it.
- Open the solution in Visual Studio.
- Right click on the solution in the Solution Explorer and click "Enable Nuget package restore."
- Rebuild the solution.
If the packages folder doesn't exist, Nuget will create it. If a package is missing (as they all will be after you delete the folder), then it will download it. This should straighten out any mismatched references in the system.