Spaces in source folder path don't create sub-dirs in target path

[Horst12]

I made an entry for a Thunderbyte local mail-dir The full source path is C:\Users\horst\AppData\Roaming\Thunderbird\Profiles\eypx4io3.default\Mail\Local Folders-maildir The target path is simply D:\backup\mail There are no sub-dirs created in the target dir. Enclosing the source path with "" doesn't help. It only copies files from the source into the target.