trouble with 4.12.4
 

I am having trouble previewing downloads before they are finished, I use to be able to preview on 4.12.3 is this a glitch or is something wrong. I have tried multiple video files. dont work. I can preview audio files though. please help:confused:

Which player are you using? You could try VLC if you like, it has codecs installed & plays most things. Only one thing to remember... it doesn't like previewing or launching within LW for Windows users! You'll have to open your incomplete folder outside of LW to preview;) If you want to have a try, click on the link below
http://www.videolan.org/vlc/

I am using windows media player 10

I don't use WMP. Did you try to preview using another player (if you don't want to download VLC, try any other video players you have)? Is WMP 10 a recent update or have you been using it for a while? Are you getting any error messages when you try to preview with WMP?
If all else fails, maybe you could try VLC:)

Well, sorry to butt in but, Windows Media Player 11 is wonderfer if you would like to give it a go.