"Folder in use" prevents moving local directories in Windows
The WinSCP Commander interface holds onto local folder references even when browsing outside the folder. Consequently Windows will not allow deleting or moving a folder if you have ever visited it. The error in Windows Explorer is "Folder in use." Within WinSCP Commander the error is a generic "error deleting." The quick workaround I've found is to exit and restart WinSCP. Sometimes I can move the folder within WinSCP and then it is released.
Suggest: Command / Clear Caches should release all folder references.
OK, so if you open a session, navigate to any local folder using "Open Directory" command/button and then you click Back command/button - At that moment you cannot delete the previously visited directory anymore?