To play .dav video files, you will need to use Amcrest Smart Player, which is a video player similar to Windows Media Player or Quicktime.
Please click here to download the Amcrest Smart Player software for PC.
Please click here to download the Amcrest Smart Player software for Mac.
Once installed and you have run the Amcrest Smart Player you will need to associate the .dav file format.
Note: Make sure to copy the .dav files over to your computer off your external drive. It will not play directly from your external drive.