I'm having another issue with this checkbox and it is this. When not checked, copy proceeds normally. When checked, I am getting an error "cannot create directory" if the directory already exists on the target.
Please start a new thread and attach a full log file showing the problem (using the latest version of WinSCP).
To generate 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 may email it to me. You will find my address (if you log in) in my forum profile. Please include link back to this topic in your email. Also note in this topic that you have emailed the log.
Please note this was added by user dt126 and not me. I have emailed you the log file pertaining to my problem and described it further above and am still having the original problem this thread is related to. Please don't abandon my request, thanks!