<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 5.15.9

Error message:
External exception C000001D

Stack trace:
(0000F031)
(00080DDE)ntdll.dll
(0008311C)ntdll.dll
(0008344B)ntdll.dll

Status: unknown_rel_addr

The problem happens rarely. I cannot reproduce it.