@segun: 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 6.1

Error message:
Invalid access to memory.

Stack trace:
(0002CCF0)
(01004C0A) C6085_3
(01006C72) ____ExceptionHandler
(01003A2C) __ExceptionHandler
(0008239F) ntdll.dll
(0006FEFA) ntdll.dll.KiUserExceptionDispatcher
(00C86946) _plug_closing_winsock_error
(00C6C0F8) _ssh_conn_processed_data
(00C1958A) C3225_0
(00C1967D) _run_toplevel_callbacks
(00D6CB13) TSecureShell::EventSelectLoop
(00D6BD7F) TSecureShell::WaitForData
(00D66919) TSecureShell::Init
(00D66258) TSecureShell::Open
(00DF797D) TTerminal::Open
(00D2183F) TTerminalThread::TerminalOpenEvent
(00D1C648) TSignalThread::Execute
(000CD80B) Userinterface::C20_0
(000152C2) KERNEL32.DLL.BaseThreadInitThunk
(00060CA7) ntdll.dll
(00060C6F) ntdll.dll

(01005275) C6085_3
(0100684F) _ReThrowException
(00D66A2B) TSecureShell::Init
(00D66258) TSecureShell::Open
(00DF797D) TTerminal::Open
(00D2183F) TTerminalThread::TerminalOpenEvent
(00D1C648) TSignalThread::Execute
(000CD80B) Userinterface::C20_0
(000152C2) KERNEL32.DLL.BaseThreadInitThunk
(00060CA7) ntdll.dll
(00060C6F) ntdll.dll

(01005275) C6085_3
(0100684F) _ReThrowException
(00D66AC6) TSecureShell::Init
(00D66258) TSecureShell::Open
(00DF797D) TTerminal::Open
(00D2183F) TTerminalThread::TerminalOpenEvent
(00D1C648) TSignalThread::Execute
(000CD80B) Userinterface::C20_0
(000152C2) KERNEL32.DLL.BaseThreadInitThunk
(00060CA7) ntdll.dll
(00060C6F) ntdll.dll

(01005275) C6085_3
(0100684F) _ReThrow

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.