Apple has apparently decided to stop supporting QuickTime on Windows. The software is often installed with iTunes and some third party applications use the interface for working with MOV and MP4 files. Windows users may wish to uninstall QT or at least stop using the app for video playback.
There have been some suggestions that the application could be re-named e.g. changed from QuickTimePlayer.exe to QuickTime_OLD.exe. That would disable the program whilst leaving the video codecs installed.
Adobe aims to offer native support for all video applications.