Transfer complete but source and destination differ a LOT

I am sure there's an easy explanation for this but I'm trying to back up a folder to a remote machine and it's about 52GB, mainly photographs, but some other misc stuff too. I have run it twice and used the "No to All" option to not overwrite pre-existing files, and it's now done. Only the source folder has 4,204 files and the destination has 4,129. Nothing happens when I hit "compare directories" and I am worried that these files may be important. Are they hidden files? Is there a setting to use to dump ALL files no matter what?

Thank you for any help in what I hope is an easy question to answer! Probably I'm doing something wrong.

Are you able to identify what's different yourself? Can you show us a screenshot of the difference?

No, it's been tough to identify what's different. Is there a way to use "diff" over SCP to tell the difference? The "compare folders" option just seems to hang. :-(

Can you send me an email, so I can send you back a debug version of WinSCP to track the problem? Please include link back to this topic in your email. Also note in this topic that you have sent the email. Thanks.