Please update your extraction software if you have issues extracting files, we have recently switched to rar5 archives because they offer better recovery protection as well as a lot of other good features.
If you suddenly have issues extracting the files you download you most likely have a really old extraction software installed. We recommend getting the free software 7zip from their official website: https://www.7-zip.org/download.html
If you are on Mac you can use the program UnArchiver (make sure you have a new version though): https://itunes.apple.com/us/app/the-unarchiver/id425424353?mt=12
That is all.