Microsoft has updated the Desktop App Converter Base Images (.WIM) and is available for download for use with the Desktop App Converter app available in the Windows Store.
Desktop App Converter is a tool that enables you to bring your existing desktop apps written for .NET 4.6.1 or Win32 to the Universal Windows Platform (UWP). You can run your desktop installers through the converter in an unattended (silent) mode and obtain a Windows app package that you can sideload on your machine or upload to the Windows Store.
For installer based conversions Desktop App Converter requires you to obtain a Windows 10 base image (.wim).
Visit https://aka.ms/converterimages to obtain the base image matching your host operating system.