martin wrote:

Please read documentation:
https://winscp.net/eng/docs/resume#automatic

this issue might be because the user's files fall below the (configurable) threshold for the automatic transfer-to-alternate-name-then-replace-original behavior (100kB) ?

probably a good moment to mention
https://winscp.net/eng/docs/library_example_verify_file_checksum
"Verify checksum of a remote file against a local file over SFTP/FTP protocol"

It might be a valuable enhancement if the Synchronize feature (or any SFTP/FTP transaction)
https://winscp.net/eng/docs/guide_synchronize
could have a "Verify" option. Should the user request file transfer verification and the server is unable to checksum/CRC, then a warning would be appropriate.

OTOH, with FTP and a server that supports XCRC/HASH/XSHA1/XMD5 extension(s), verification would be roughly equivalent as using SFTP alone. SFTP running on top of SSH2 has stronger integrity checking than over SSH1, so requesting file transfer verification should insist on at least SSH2 to the server (and then checking timestamp and file size post-transfer would be verification enough).

Please read documentation:
https://winscp.net/eng/docs/resume#automatic

I would like to see a feature where files can be uploaded as a temp file then the completely uploaded file is renamed or moved to its correct file name.

Currently when I upload a PHP file to my server a request for that file may have incomplete contents preventing the web app from loading. This should prevent this from happening.