Whenever I try to drag and drop a file to a directory where a file with the same name exists, instead of prompting me to overwrite the file, it dies with the above error message (General failure, error code 4). I have to hold down the ctrl key and drag to copy the file, and then delete it later. This is very time consuming and error prone, because it's too easy to delete the wrong file after copying. It also adds an extra step, which slows me down a lot.
Why can't I get WinSCP to prompt me to overwrite existing files on drag-and-drop move?