@jinetelogico: Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<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 6.5.5

Error message:
Out of memory

Rastreo de la pila:
(001F2745)
(001F2745)
(001F8F24)
(001F8DE8)
(00416EB9)
(001FA570)
(001FB890)
(001FBC60)
(001FA539)
(001F9F31)
(00202AAF)
(001FA182)
(001F1B65)
(001F1B2A)
(00506C12)
(004F1065)
(0039E3C2)
(003A356D)
(0041B07F)

Status: unknown_rel_addr

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.