I'm trying to recreate the problem but I cannot do it. If I get the problem again I'll start the winscp-debug version.

Thanks for your report.
I have sent you an email with a debug version of WinSCP to address you have used to register on this forum.

I found the problem.
It was due to a file [LnPy_B2221750221719?] in the refreshing directory containing a question mark at the end of the name.
Removing that file winscpo works fine.
Kind Regards
Loreto

I was jut refreshing the directory (ctlr-R)
Attached file shows the winscp screenshot.
I worked normally for several days without problems. Nothing shoul be changed in my operations.

WinSCP 5.6.2

Error message:
Error listing directory '/home/pi'.

Unexpected directory listing line ''.
Range check error

Stack trace:
[01A06015]
[01A07548]
[018A353E]
[018B0496]
[018AFE50]
[01937515]
[0193616C]
[0184098C] @TUnixDirView@ReloadDirectory$qqrv
[0126366E]
[015B0DCC]
[013988FD]
[01653CC2] @Tb2item@TTBPopupMenu@IsShortCut$qqrr22Winapi@Messages@TWMKey