CuteFTP Pro will attempt to resume broken downloads and uploads automatically.
If you have interrupted a transfer and you need to resume the transfer, simply attempt to transfer the file into the same directory you did the first time. CuteFTP Pro will then prompt you and ask if you wish to Overwrite, Skip, Resume, Rename, or Numerate. Choose Resume.
To check if the FTP site your are connecting to can resume a user aborted download, watch the status window for a message that reads This site can resume aborted downloads during login. If the site cannot resume the download, you will get the message This site cannot resume aborted downloads. To resume uploads the server must also support the Unix command APPE.