The beta version seems to have corrected the problem. I no longer get the error message reported in my original post.

All is good. :D

I will install the beta and report back when I get home next week.

I hope this have been fixed already in 4.3 beta.
https://winscp.net/tracker/622

Thanks to Martin's help in another thread I just discovered how to set Preferences to allow multiple files to transfer in the background automatically. However, I've found that now when I transfer some groups of files I get the error message listed in the subject of this message: String list does not allow duplicates.

I haven't been able to pin down exactly when or why I get the error but it seems that only certain files in the group selected for transfer cause the error.

When I'm doing the transfer in question I want to overwrite existing files. Is there some permission I need to set or change to avoid getting the error message I'm seeing?

Thanks for any clarification.