Stefan said in Community Project | Cardinal Menu System Instructions, Help, and Discussion:

Hi, I downloaded your project files, but when I need to rebuild I get error: "CardinalMenu could not be compiled. Try rebuilding from source manually". I tried on every version of your project, on 3 different pc and no luck, please can you help me? I use Microsoft Visual Studio 2015 Enterprise

Do you have this problem on all UE4 projects with source code? I've had this problem for many various reasons in the past. You can try this.

Right click on CardinalMenu.uproject and select Generate Visual Studio project files. It should have created CardinalMenu.sln in the same directory.
Open CardinalMenu.sln
In Solution Explorer (typically on the right) open Games -> CardinalMenu
Right click on CardinalMenu in Solution Explorer and click rebuild.
A log should appear on the bottom and show you errors.
Paste this log here and I'll look at it.

Other Possible Solutions
A common problem I get is Visual Studio logs my credentials out for some reason. I have to open Visual Studio and on the top right there's a drop down arrow and it says "An error has occurred and we can no longer retrieve user information for... " I then have to log in. This might be in Community Edition only though. I haven't used the enterprise version of VS 2015. Only older versions.

Another problem is the C++ compile add ons might not be included with your install of VS2015. Is this the first project you've used for UE4? Usually this happens when someone first starts messing around with Unreal 4 or they are using a new computer. Here's the solution.
"Visual Studio 2015 (VS2015) doesn't install C++ tooling support by default. When installing VS2015, choose Custom installation and then choose the C++ components that you'll need for your workflow. If you've already installed Visual Studio 2015, choose File > New > Project > C++ to install C++."