Many users may see half of your video preview chopped off (black banding) in muvee software products. This is caused by a bad patch from Microsoft Windows Security Update (KB2803821) for Windows 8, 7 and Vista ; Windows Security Update (KB2834904) for Windows XP. The only workaround at the moment is to UNINSTALL this MS Update.
Microsoft has fixed the issues for these users. Run Windows Update again and the re-released 2803821 patch should fix the half-video preview issues. We have just verified this fix on Windows 7 machines.