Re: Solved
                In GUI, you can set that option in preferences:
https://winscp.net/eng/docs/ui_transfer_custom
        https://winscp.net/eng/docs/ui_transfer_custom
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
"C:\Program Files (x86)\WinSCP\WinSCP.exe" /rawtransfersettings ReplaceInvalidChars=0
crystal-HC49%2fS.kicad_mod. 
%2f will be seen as / char and WinSCP fails saying
scp: error: unexpected filename: crystal-HC49/S.kicad_mod
Whatever%20%20prec.jpg.