<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 5.17.9

Error message:
Invalid access to memory.

Stack trace:
(00C3D5CB)
(00087D6F) ntdll.dll
(00073211) ntdll.dll.KiUserExceptionDispatcher
(0000A245)
(003E9430)
(001C7FCE)
(00239E36)
(00239EB4)

Status: unknown_rel_addr

The problem happens rarely. I cannot reproduce it.