If QuickTime fails to open your file, then it seems your application installation is outdated or incompatible. The QuickTime player may be too old and thus it is not able to read the file. So, update your player first. But, when it comes to updating the QuickTime version, it is not obligatory to uninstall it completely then, re-install. This video shows how to install Apple Applicationlink to download winrar if you need it to extract the files:https://www.rarlab.com/download.htm. I was using Quick Time Player because that is how the items I wanted to view are sent to me. I have Quick Time Player now on my system BUT I get the message to install 'Apple Application Support'. Unlike installing the 'Player', I can NOT install the 'Application'. It will not install (Windows 7) no matter what I tried.