If the disk quota has been exhausted on the server and you go to edit a file
you'll get the following error and the original file on the server GETS DELETED.
"Copying files to remote side failed"
General failure (server should provide error description).
Error code: 4
Error message from server: Failure
Request code: 6
Does WinSCP delete the Original, then upload the newly modified file?
If so, this is flawded. It should upload the modified file with a temp name
and after a successful tranfer, delete the original and rename the temp.