RouteConverter.exe cannot save files

This happens when your Documents folder has been moved to another drive. Windows Defender's controlled folder access then blocks writes from apps it does not fully trust, and RouteConverter.exe cannot save.

Fix

Allow RouteConverter.exe through controlled folder access:

Settings → Update & Security → Windows Security → Virus & threat protection → Manage settings → Controlled folder access → Allow an app through controlled folder access → Add an allowed app, then add RouteConverter.exe.

Note

The RouteConverter.jar build is not affected by this problem.