OK, use

See https://winscp.net/eng/docs/rawtransfersettings
(edited 2022)

No combination of parameters caused the synchronize command to behave this way:

• Leave alone remote files not present locally
  
• Upload local files that do not exist remotely
  
• Resume remote files where the local copy is larger
  
• Skip remote files where the local copy is the same size
  

I tried many combinations and could sometimes satisfy a set of those requirements but never all.

What does it mean "doesn't seem to correctly resume or skip"?

As a script at least using winscp.com, synchronize doesn't seem to correctly resume or skip regardless of options set when using FTPS. I had started there but gave up using it when I found success with put. Does it behave differently here?

Use Session.SynchronizeDirectories:
https://winscp.net/eng/docs/library_session_synchronizedirectories
https://winscp.net/eng/docs/scriptcommand_put#net

Hello-

I've been experimenting with WinSCP for uploading to an FTPS file server. Using a script file, I can upload files and automatically resume or skip existing files as is appropriate using:

However, I've been trying to replicate this behavior using the .NET assembly and have not found an equivalent to the -neweronly flag available in winscp.com. Neither the SessionOptions class nor TransferOptions class seems to have criteria for when to resume.

Is this feature available? Some files I'm uploading are hundreds of megabytes, so this could potentially consume a large amount of time for data which is already on the server.

Thanks,
Geoff