Error:

The adapter failed to transmit message going to send port “sp_Test_SFTP” with URL “sftp://sftp.mycompany.com:22/%MessageID%.xml”. It will be retransmitted after the retry interval specified for this Send Port. Details:”System.IO.FileLoadException: Could not load file or assembly ‘WinSCPnet, Version=1.2.10.6257, Culture=neutral, PublicKeyToken=2271ec4a3c56d0bf’ or one of its dependencies. General Exception (Exception from HRESULT: 0x80131500)
File name: ‘WinSCPnet, Version=1.2.10.6257, Culture=neutral, PublicKeyToken=2271ec4a3c56d0bf’ —> System.Exception: SFTP adapter requires WinSCP to be installed. Please refer http://go.microsoft.com/fwlink/?LinkID=730458&clcid=0x409 . —> System.IO.FileNotFoundException: Could not load file or assembly ‘file:///C:\Windows\Microsoft.Net\assembly\GAC_MSIL\Microsoft.BizTalk.Adapter.Sftp\v4.0_3.0.1.0__31bf3856ad364e35\WinSCPnet.dll’ or one of its dependencies. The system cannot find the file specified.

Solution:

I think BizTalk requires a specific older version of WinSCP and you can’t just download the latest one.
This error could also occur if you didn’t copy the file to the proper directly.

I found Michael Stephenson’s BizTalk 2016 SFTP blog, and it had a nice PowerShell script.

Updated: Jan 19, 2021 – This is now an improved Powershell Script to install the proper version of WinSCP for BizTalk 2016 or BizTalk 2020, you can copy/paste it from this page: https://www.phidiax.com/blog/post/biztalk-server-auto-install-script-for-sftp-requirement-of-winscphttps://pvandenheede.wordpress.com/2019/02/14/biztalk-2016-cu5-gotcha-upgrade-winscp-to-v5-13-1/

It’s smart enough to know which version of WinSCP to install for BizTalk for the most recent releases, features packs and cumulative updates.

I just had to
1) Change directory names (I had a Software directory similar to him, but I had to create a WinSCP subdirectory under it)
2) Then PowerShell with the “Run as Admin” option.

Then the script ran fine, I restarted BizTalk Host Instance, and it got past this error, on to other errors that I’ll blog about in the near future.

By the way, I was able to run in a 64-bit host with no problem.  I remember that in older version of BizTalk the FTP adapter ran only in 32-bit hosts.