For some reason, the site I connect to doesn't work well with the "Optimize connection buffer size" enabled, and whenever I had that on while downloading files larger than a few megabytes, I'd get this error: Server unexpectedly closed network connection.

Fortunately, I found how to turn it off and (in the GUI version at least) all my transfers are successful. On the contrary, in batch mode from a script file, even after setting "-rawsettings SendBuf=0" appended to the open command, the connection will "unexpectedly close" on files larger than a few megabytes.

Does SendBuf=0 completely turn off the feature as the GUI checkbox does?

Thank you.

Yes it does.

Please attach a full log file showing the problem (using the latest version of WinSCP).

To generate log file, use /log=path_to_log_file command-line argument. Submit the log with your post as an attachment. Note that passwords and passphrases not stored in the log. You may want to remove other data you consider sensitive though, such as host names, IP addresses, account names or file names (unless they are relevant to the problem). If you do not want to post the log publicly, you can mark the attachment as private.

I attached the log files and have reproduced the problem again. Thank you.

OK, I was wrong. Try also setting SshSimple=0

Thank you. That works.

Hey,

I'm trying to rename files in a SFTP and it works, but after a few files renamed, suddenly the below text is written in the log and the exception is never thrown.
. 2016-01-28 12:46:06.719 --------------------------------------------------------------------------
. 2016-01-28 12:46:06.719 Looking up host "sftp.cleanharbors.com"
. 2016-01-28 12:46:06.719 Connecting to 12.15.160.40 port 22
. 2016-01-28 12:46:06.938 Server unexpectedly closed network connection
. 2016-01-28 12:46:06.938 Knocking FTP port.
. 2016-01-28 12:46:07.079 FTP port opened, will suggest using FTP protocol.

I already set SendBuf=0 and SshSimple=0
I'm using C#
sessionOptions.AddRawSettings("SendBuf", "0");
sessionOptions.AddRawSettings("SshSimple", "0");

Any thoughts?

Thanks.

That piece of log is hardly related to file renaming.
Please start a new thread and attach a complete log. The options SendBuf and SshSimple are absolutely not related to this problem either.

Hello,

I have the same problem.
-rawsettings SendBuf=0 SshSimple=0 don't help

Interesting is that after many attempts finally the file is uploaded successfully.
Please see log file.

Can I have a test account on your server?