<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 5.7.7

Error message:
Invalid access to memory.

Stack trace:
(007E0326) __DynamicCastVCLptr
(0008A61F) ntdll.dll

Status: all_insignificant

The problem happens rarely. I cannot reproduce it.