Firefox does not download from certain web sites or certain file types. For example, in an attempt to download Adobe reader from Adobe web site, after clicking the download - button, a new window appears with the name of the file in the location bar. However, the page appears as if charging infinitely and does not download at all. The same happens also i.e. when trying to download Safari. I have cleared my downloads history, reset all my preferences, reset download actions for all file types and checked the Mac OS firewall. None of this has helped.