For installer based conversions Desktop App Converter requires you to obtain a Windows 10 base image (.wim). Please visit https://aka.ms/converterimages to obtain the base image matching your host operating system.
Documentation - https://aka.ms/converterdocs
Video tutorials - https://aka.ms/convertervideos
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 an Windows app package that you can sideload on your machine or upload to the Windows Store.
This developer tool is required to be run under administrative privileges.