Synchronization or keep remote directory up to date functions are not working. Why?

You may experience one or more of following problems while synchronizing files:

• All files are transferred every time, although only some files were changed.
• Changed files are not transferred at all.
• Changed files are transferred only sometimes.

Actions/Checks to do to resolve the synchronization problems:

• In all above cases the problems is usually caused by WinSCP not correctly converting timestamps from local conventions to remote server conventions and vice versa.
• See documentation to learn about other possible problems with timestamps.
• Learn how to troubleshoot issues with timestamps.
• Also with FTP and WebDAV protocols, the server may not support preserving timestamps of uploaded files. Usage of synchronization in local to remote direction is limited then.
• Also note that filename modification logic for file transfers applies also, when comparing files for synchronization. So file names with special characters that are seemingly different may actually be considered the same by WinSCP.
• Another possibility is that you have enabled Size synchronization criteria and also Text (or Automatic) transfer mode. Those cannot work together, as file size changes in the Text transfer mode.