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

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.17.6

Error message:
メモリのアクセス違反

スタック トレース:
(0021B7A8) Vcl::Graphics::TBrush::SetColor
(00087E3F) ntdll.dll
(000732D1) ntdll.dll.KiUserExceptionDispatcher
(00275321) Vcl::Controls::TControl::WndProc
(00274F5C) Vcl::Controls::TControl::Perform
(0027A30E) Vcl::Controls::TWinControl::PaintControls
(00274129) Vcl::Controls::TControl::Repaint
(00085A1C) TFrameAnimation::Repaint
(003A4AC8) System::Classes::_18201
(000434B9) USER32.dll
(00023FF7) USER32.dll
(00023149) USER32.dll
(00022F2B) USER32.dll.DispatchMessageW

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.