The first URL you posted: GroupDocs.Viewer-for-.NET-MVC-App - goes to https://github.com/groupdocs-viewer/GroupDocs.Viewer-for-.NET-MVC-App
This is the URL I cloned - as stated in the original post. I just cloned it again in case and I have built the Viewer-Modren-UI.sln solution with Visual Studio 2015.
Firstly I can see that the rest of the demo files are no longer in the solution.
Two demo files were deleted in commit 56b9136c2aefc9ae5fe63f931e95f1d26961ea1e by email@example.com on 15/03/2018 19:44
calibre.docx is still in source control, but is missing from the project file.
From source control, the solution does not build - there is an error:
D:\gd3\Viewer-Modren-UI\Viewer-Modren-UI.csproj(184,5): error : This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them. For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is D:\gd3\.nuget\NuGet.targets.
To make it build I removed the
<Target Name=“EnsureNuGetPackageBuildImports” BeforeTargets=“PrepareForBuild”> section from the Viewer-Modren-UI/Viewer-Modren-UI.csproj project file.
I also changed the _licensePath from “D:\License\GroupDocs.Total.lic” to “D:\GroupDocs.Viewer.lic” as we have a viewer licence.
Having done a clean clone of the source and with the changes described above, the calibre.docx file is rendering correctly. Thanks for taking the time to check it on your end. I will proceed to check that other documents we previously had issues with now show correctly in this Modren UI example.