I am running Parallels Desktop 9, and Mavericks as both the host and guest OS. All updated as of today, and Parallels Tools installed. I have problems with video output in the guest OS: An arbitrary mp4 file is playable with Quicktime but not with VLC. No matter which settings I try in VLC, the result is the same: No video output. For a very short period of time (tenth of a second) a window with a black screen opens but then immediately closes. In the host OS the file is playing perfect with both Quicktime and VLC. Any ideas why the video output is not visible? I have actually tried with MPlayerX as well but with negative result. A windows is opened, however it is completely black when the file is running. Also tried with Mountain Lion as the guest OS, no luck. Running QuickTime is no prion since I have many other types of videos that VLC normally plays but QT doesn't. Please help! /Anders