If for any reason, the advanced uploader fails to upload the files successfully, you can try clearing out your java cache and temporary files.
On a Mac:
- Open System Preferences and open Java (usually found at the bottom of the screen).
- On the Java Control Panel window, on the General tab and under Temporary Internet Files, click on Settings.
- On the Temporary Files Settings window, click Delete Files.
- Select all three options and click Ok.
Now, log back into Canto and open the advanced uploader.