<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 5.9.6

Error message:
Ошибка доступа к памяти.

Трассировка стека:
(0028EEE0)
(00081CFF) ntdll.dll

Status: unknown_rel_addr

The problem happens rarely. I cannot reproduce it.