sudden invalid or not supported file error Video

I have an mp4 video that was working fine for two months, today upon booting up the thumbnail is not visible, and the video player is blank. I tried to re-load but got he invalid video file message, it wont load. Any idea how fix & why this would happen suddenly. I am on 6.5.0 have not updated because i am completing a big project. Thx ! :sunglasses:

Try to use last update of Cubase 6.5, i.e. 6.5.3, which is completely supported, now. Try to reinstal used video codec.

the update did the trick, thanks for the reply

I’m having this same problem, however i’m using Cubase artist 7, i dont get an “invalid video file message” the video just wont play and the thumbnail is missing.