Yahoo! Briefcase is closing on March 30.
So, I was downloading the files I had in my Yahoo! Briefcase, and noticed that certain files were not downloading. I also noticed that my folder name and one of my file names had an exclamation point in them. I edited these to remove the exclamation points, and, lo and behold, the downloads worked. Kind of ironic considering the site uses an exclamation point as part of their branding. You would think they would have tested that case.