These files are very large and are compressed zip folders. If you download and attempt to open the folder before your browser has completed the download, you will get an error. Be patient, watch your web browser's download progress indicator and wait for the download to complete. Once completed, feel free to open the folder on your desktop. THAT BEING SAID, If you already tried to download the folder and keep getting an error it’s because your browser thinks it has a fully downloaded file but in reality, the download was interrupted (by trying to open the file too early) and you may have a corrupted, partial download. If this happens go to your “Downloads” folder and delete the partial download, empty your trash and reload the web page before clicking the link again.
To open a Zip file, double-click the icon.