Well, WinSCP didn't do anything to add this "functionality". It was added by Windows in some past Windows 10 build. Now they seem to have removed that. Hard to tell, if it was by purpose or by mistake. Let's see what they respond.
Did you think this is an Windows Error?
So, i have sent a error message via feedback hub and gave him a link to this forum/error.
OK, so will you please report this to Microsoft?
Hello mate, since windows 1903 i have the error code 1155 with unknown file extension.
I have this error (actualy) only with Winscp.
In Windows 1809 i can look for the correct software in Winscp but with Windows 1903, Winscp did not show me this window.