<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:
Invalid access to memory.

Stack trace:
(0029466B)
(00087AEF) ntdll.dll
(00073FB1) ntdll.dll.KiUserExceptionDispatcher
(00214D98)
(00040379) USER32.dll
(00037345) USER32.dll
(000350B5) USER32.dll
(00034E7B) USER32.dll.DispatchMessageW

(00294258)
(00087AEF) ntdll.dll
(00073FB1) ntdll.dll.KiUserExceptionDispatcher
(00214D98)
(00040379) USER32.dll
(00037345) USER32.dll
(000350B5) USER32.dll
(00034E7B) USER32.dll.DispatchMessageW

Status: unknown_rel_addr

The problem happens rarely. I cannot reproduce it.