Hi, I did just finish my Yosemite clean install and all seems well so far, except that I can not get Perian for QuickTime working. When I download the latest version (1.2.3) and open a .mkv file, it starts to convert it, but not to play. The same for .avi, QuickTime wants to convert it but not play directly. This is very annoying. Some body experienced the same or has a fix for me? In the Finder when I click on "Go" and hold alt to reveal Library under Lion (10.7.) there was a folder Quicktime with Perian in it. Before my Yosemite clean install I copied this folder, but under Yosemite there is no such folder at all. Also the system does not try to access the folder, the date stays untouched. In System Preferences I got the Perian symbol after installation, but as mentioned it wants to convert the files to play them. When I deinstall Perian, then QuickTime does not allow me to open .mkv & .avi at all. Has someone an idea?