<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 5.9.1

Error message:
Acceso a memoria no válido

Traza de la pila:
(006FA2F8) TSecureShell::LogEvent
(00862736) C5073_3
(0086479E) ____ExceptionHandler
(00861558) __ExceptionHandler
(00062496) ntdll.dll
(0000F13E) ntdll.dll.KiUserExceptionDispatcher
(006F5D76) TSecureShell::Open
(0076C94A) TTerminal::Open
(006C5D67) TTerminalThread::TerminalOpenEvent
(006C0D3C) TSignalThread::Execute
(000986B3) Userinterface::C20_0
(00012388) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

(00862DA1) C5073_3
(0086437B) _ReThrowException
(0076CADF) TTerminal::Open
(006C5D67) TTerminalThread::TerminalOpenEvent
(006C0D3C) TSignalThread::Execute
(000986B3) Userinterface::C20_0
(00012388) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

(00862DA1) C5073_3
(0086437B) _ReThrowException
(0076CF41) TTerminal::Open
(006C5D67) TTerminalThread::TerminalOpenEvent
(006C0D3C) TSignalThread::Execute
(000986B3) Userinterface::C20_0
(00012388) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

The problem happens rarely. I cannot reproduce it.

I am facing this problem ,due to which not able to proceed my process.Could you please resolve this and let me know why this happened ?
WinSCP 5.7.6

Error message:
Invalid access to memory.

Stack trace:
(006A7A78) TSecureShell::LogEvent
(007E46BA) C4799_3
(007E6722) ____ExceptionHandler
(007E369C) __ExceptionHandler
(00062496) ntdll.dll
(0000F13E) ntdll.dll.KiUserExceptionDispatcher
(006A34F9) TSecureShell::Open
(0070C642) TTerminal::Open
(00674BF7) TTerminalThread::TerminalOpenEvent
(0066FBD8) TSignalThread::Execute
(0008269F) Userinterface::C21_0
(00012388) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

(007E4D25) C4799_3
(007E62FF) _ReThrowException
(0070C76C) TTerminal::Open
(00674BF7) TTerminalThread::TerminalOpenEvent
(0066FBD8) TSignalThread::Execute
(0008269F) Userinterface::C21_0
(00012388) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

(007E4D25) C4799_3
(007E62FF) _ReThrowException
(0070CB6E) TTerminal::Open
(00674BF7) TTerminalThread::TerminalOpenEvent
(0066FBD8) TSignalThread::Execute
(0008269F) Userinterface::C21_0
(00012388) kernel32.dll.BaseThreadInitThunk
(00038900) ntdll.dll
(000388D0) ntdll.dll

The problem happens rarely. I cannot reproduce it.