WinSCP may skip a change, if a file is changed within the same minute and the server does not provide second-precision timestamps (common with some FTP servers, notably the IIS).
See https://winscp.net/eng/docs/timestamp

Though this has been improved recently, pending release (in few days):
Issue 1395 – When FTP server does not provide precise timestamp, but the timestamp otherwise matches timestamp of the last uploaded version of the file, using precise timestamp of the uploaded version instead

Hi,

first of all, thanks for this great program. I've been using it for years.

There's a problem that I can't reproduce reliably, but it has been occurring for a long time, with different computers, Windows versions and WinSCP versions.

The "Keep remote directory up to date" mode sometimes doesn't notice when I change a file. I use that mode to develop websites. I have a local copy of all HTML files etc. that I work on, and WinSCP copies my changed files to my webserver.

I think it mostly happens when I copy a whole batch of changed files, as if WinSCP didn't react quickly enough.

Does anyone else know this problem and maybe how to solve it?

Thanks!