What to do if Video files and DVD movies cannot be viewed on the computer LCD and the external display at the same time?
Unable to view video files and DVD movies on the computer LCD and the external display at the same time.
A video file may not display properly on an external display while viewing the same video file on the internal LCD. The video file may not display on an external display depending on the type and CODEC of the video file being played, the copy protection of the video or DVD being played, or the compression methods and the amount of video processing needed to decode the video.
For these reasons, it is recommended that the video file or DVD be played back on a single display only, either the LCD or the external display. To toggle between display options (LCD only, external display only, or both LCD and external display), press the FN+F7 keys until the desired display setting is selected.