The Visual Studio C# projects included with the VenturaSQL templates have their NuGet packages folder deleted. This was done to keep the VenturaSQL installer small.

The NuGet packages folder contains downloaded NuGet packages, which are mostly referenced assemblies (DLLs).

Visual Studio needs to restore the packages folder by downloading the packages again.

Yellow exclamation triangle

Visual Studio marks the missing references with a yellow exclamation triangle:

Method 1: Rebuild Solution

In Visual Studio go to Build -> Rebuild Solution. Visual Studio may need some time to download and install the packages. The exclamation triangles should disappear:

Should this method not work for some reason, then use Method 2.

Method 2: Force restore in the NuGet Package Manager

In Visual Studio go to "Tools > NuGet Package Manager > Package Management Console"

In the Package Manager Console window then enter the following command:

Update-Package -reinstall

This will force re-installation of all packages for the opened solution.