Aux wrote:

I know that such behaviour is somehow related to timestamps, yet I think using timestamps in keep up to date is wrong: WinSCP already detects file changes, so why to compare timestamps/sizes? Just push changes to remote host! At least such option could be added.

This is explained here:
https://winscp.net/eng/docs/task_keep_up_to_date#how_it_works

I know that such behaviour is somehow related to timestamps, yet I think using timestamps in keep up to date is wrong: WinSCP already detects file changes, so why to compare timestamps/sizes? Just push changes to remote host! At least such option could be added.

P.S. I'm using GUI mode, Win7 x64 Pro, SFTP, there are no errors reported.

Sorry, your post does not include enough information.

Please read how to troubleshoot problems with WinSCP. If it turns out that you are not able to help yourself, read how to ask for support or report bugs efficiently, so others can help you.

Also see https://winscp.net/eng/docs/faq_synchronize

I'm using WinSCP 5.1.7 (latest version available) and update function does not work. In dialog log I see that WinSCP detects file changes on my PC, but it does not upload changed files anywhere. Tried different settings to no effect.