<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 5.17.2

Error message:
Invalid access to memory.

Stack trace:
(004180A3) System::DoneExcept
(00045CD6) ntdll.dll.RtlRaiseStatus
(00045B62) ntdll.dll.KiUserExceptionDispatcher
(003A4578) System::Classes::_18201
(0001B264) USER32.dll
(0001B362) USER32.dll
(0001B994) USER32.dll
(0001B9EB) USER32.dll.DispatchMessageW

(00417C90) System::HandleAnyException
(00045CD6) ntdll.dll.RtlRaiseStatus
(00045B62) ntdll.dll.KiUserExceptionDispatcher
(003A4578) System::Classes::_18201
(0001B264) USER32.dll
(0001B362) USER32.dll
(0001B994) USER32.dll
(0001B9EB) USER32.dll.DispatchMessageW

Status: all_insignificant

The problem happens rarely. I cannot reproduce it.