you have figured it out but i will reply so if people coming to this thread with the same question know ow to do it.
open windows explorer and browse to your Launcbox folder and open the data folder located inside. using your plaintext editor like notepad open bigboxsettings.xml locate the <VideoPlaybackEngine>, and change it to <VideoPlaybackEngine>Windows Media Player</VideoPlaybackEngine>. then save and close the file.
Hi,
when BB is loading the screensaver big box crashes, no error messages on screen just hard crash.
Changed to FFMPEG from WMP, will check if changing bck makes a difference