A red button reboot would be a first step but wouldn't get you the new software.
If you haven't done a RBR, try that first. If you still have the problem after a RBR, then I'd try new software.
To start that process, do another RBR. After you do the RBR, the moment you either get the blue screen on your TV, or the blue lights come on your DVR, press 0-2-4-6-8 on your remote. Do it deliberately. Do it once.
If everything happens right, you'll soon see a notification on your TV that the DVR is downloading the software again.
If you don't see that in a minute or so, immediately do another RBR and try again. It might take you a few attempts to force your DVR to re-download its software.