This is a major bug! I edited a route for an upcoming trip from Florida to Colorado and can't save the Excel copy to my computer. I only get an error message that the filename cannot be found... Duh, it's a new file!
In the latest version of Firefox on windows this should work. However, Pop-ups need to be allowed for the website.
How is the error message displayed? By the browser or when you search your file system in the computer?