<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 6.1.1

Error message:
メモリのアクセス違反

スタック トレース:
(0029466B) System::DoneExcept
(00087A5F) ntdll.dll
(00073F81) ntdll.dll.KiUserExceptionDispatcher
(00214D98) System::Classes::_18201
(00040109) USER32.dll
(000370C5) USER32.dll
(00034E35) USER32.dll
(00034BFB) USER32.dll.DispatchMessageW

(00294258) System::HandleAnyException
(00087A5F) ntdll.dll
(00073F81) ntdll.dll.KiUserExceptionDispatcher
(00214D98) System::Classes::_18201
(00040109) USER32.dll
(000370C5) USER32.dll
(00034E35) USER32.dll
(00034BFB) USER32.dll.DispatchMessageW

Status: all_insignificant

The problem happens rarely. I cannot reproduce it.