Please attach a full session log file showing the problem (using the latest version of WinSCP).
To generate the session log file, enable logging, log in to your server and do the operation and only the operation that causes the error. Submit the log with your post as an attachment. Note that passwords and passphrases not stored in the log. You may want to remove other data you consider sensitive though, such as host names, IP addresses, account names or file names (unless they are relevant to the problem). If you do not want to post the log publicly, you can mark the attachment as private.
Is /xmllog (or /log) something I can simply add as a command-line option to winscp.com call inside the script file (as part of the open, or an option, or ?)?
I see it can be set inside the preferences inside the GUI. If I set it there, for the Windows user that runs the winscp.com call, inside a Windows Task scheduler job, will it be used (how does it need to be set with winscp.com?)?
The documentation I read on your latest bug fixes / in-works items seemed to indicate (saw this date in the 12.0 beta referenced) seems to indicate this might be something specific to the type of data, maybe missing a mod date (although I do a file listing in the retrieve winscp.com file, before pulling th file, and mod dates are there..., I'm inquiring in order to understand how to ask my customer about, who is putting up the files for us to pull down)?
I will get a log, but may be delayed a few days / up to a week, but please indicate how best to turn it on (I dabbled with the .Net Framework method, and will probably eventually go there, with PowerShell, and turned on log that way, but my method here is winscp.com script file, wrapped inside a perl script).
On another note, your documentation is kind of weak with perl and the .Net Framework library (only one example, having to extrapolate), is there plans to expand there, or is there someplace else to look for that?