You may find in certain cases the Loupe Agent, Packager, and LoupeViewer.exe fail complaining of a System.TypeInitializationException on Windows 10 systems.
This problem is due to Windows 10 shipping with multiple fonts with the same family name when compared in the invariant culture, something the font selection code in the various parts of Loupe didn't allow for. A fix for this issue was shipped in Loupe 220.127.116.1128 so any component with a version number of that or higher will address the issue. You can update directly from NuGet for the various components (recommended) or download the latest 3.* installation. As of Loupe 4.0, redistributables are no longer included in the Loupe installation and are only available via NuGet.