DIRECTV DVRs are insecure. They need to receive constant signals from a satellite or they begin to get very worried and eventually shut down. Usually that’s not a problem, but there are a few times you would want to use a DVR after it’s been deactivated or without satellite service.
While the DVR will give you constant errors on live TV, you can usually go to the playlist and watch recorded programs for 3-6 days. The DVR gets a signal from the satellite roughly once a week that authorizes it to continue showing programs. If DIRECTV didn’t do that, you could just disconnect your service and keep using it forever.
Once time is up, there’s really nothing you can do to get those recorded programs back. Even if you opened the case and took out the hard drive (which you should not ever do) you’d find that the files are encrypted and without the receiver they were recorded on, they don’t work.