WinSCP 4.3.7 on Windows 7. Using the GUI.
Session protocol: SSH-2
Transfer protocol: SFTP-3
When I save a file, WinSCP very frequently gives me a "Software caused connection abort" dialog. I have to switch over to the WinSCP window, close the error message, then I immediately switch back to my editor, save the file again, and then it uploads the file to the server without issue. I'm using an external editor.
This is the only error dialog I've encountered in WinSCP that doesn't attempt to automatically repeat the operation.