Launching Edge with a file URL

As noted in the comments, Edge does not support the file: protocol via the command line at this time.

However, it is currently possible to launch Edge with a local file using IApplicationActivationManager. The necessary code can be extracted from the C# version of MicrosoftEdgeLauncher and integrated into a C# application.

See 'MicrosoftEdgeLauncherCsharp' at https://github.com/MicrosoftEdge/edge-launcher. To launch with a local file, use 'file:///d:/path/filename.ext' as the arguments parameter to ActivateApplication.

One dirty solution: first set your default launcher as Edge.

Suppose the file you want to open is file:///C:/foo/bar.html, you can launch it using explorer:

explorer file:///C:/foo/bar.html

Which will open Edge with the HTML for you. This seems to be the only solution after start microsoft-edge:file:///C:/foo/bar.html no longer works.