I am having a problem with Safari (6.05) and Firefox (23.01) with Flash. When I try load up any YouTube videos I get a 'Plugin Failure' message. I'm on OS X 10.8.4 When I open them up with Google Chrome everything is fine. I tried updating my Flash with Safari and Firefox, but the download would just not begin. So I went to Chrome and it came up with a message saying that Flash is included with Chrome. I then realised it was a Flash issue with Safari and Firefox, but I couldn't download the latest Flash with them. So I had to download the Flash installer with Chrome and then run it. So after installing the latest Flash I still keep getting the 'Plugin Failure 'message. I have uninstalled any extensions in Safari and Firefox. And I have also made sure that I am not signed up for the HTML5 test on YouTube (after many google searches I see this is a common problem with other users. If anyone can help that would be great. Even though Chrome is all working fine, I prefer to use Safari and Firefox.