I have just purchased a new C210 and an external C320WS.  On both, if I do a manual video record, it saves a video file into the Memory section and I can see the thumbprints perfectly showing an image with the time length of the video.  However, when I click on the play button of the opened video file, nothing happens and the image is black.  Is it not possible to play back manually recorded videos?  It's worth saying that the automatically recorded videos after motion is detected all play back perfectly.  Just the manual ones don't.