Error BE0032: Reflection data files for the selected framework do not exist yet (platform/version)
This error will occur if the reflection data XML files for the selected framework do not exist yet. For the standard reflection data set files supplied with the help file builder, these will reside in subfolders under the %SHFBROOT%\Data\ folder, each named after the respective framework.
The XML files in the named folder are required to document members inherited from base framework classes. If you get this error, check to be sure that the SHFBROOT environment variable points to the latest copy of the Sandcastle Help File Builder and tools (usually in the %ProgramFiles(x86)\EWSoftware\Sandcastle Help File Builder folder) and that a folder exists in the .\Data\ folder named after the selected framework. If it does not, you should reinstall the Sandcastle Help File Builder.
If using the Sandcastle Help File Builder NuGet package, it may mean that you need to install one or more of the help file builder Reflection Data Set packages which contain the necessary files. If multiple versions of the platform package exist, install the latest release as it will cover all prior releases as well. Be sure to set the project's Component Path project property to the packages folder if it is not under the help file build project folder. Once installed and the component path is set, you may need to close and reopen the project in order for it to detect the newly installed files.