DirectTV Dvr Playback of Recording skipping and locking up reciever forcing Resetof reciever.
Have either of your tried unhooking the HDMI connector if you are using it and try component?
What software are you running on the unit. The HR20-700 and HR20-100 just got a software update that was going to fix this problem w/ the unplayable recordings.
If it is erasing your content that is a good sign of a defective hard drive. These units when they boot up (after a software update) check the hard drive. If they run into a problem (bad sector) they will foolishly erase the hard drive, thus erasing everything you have recorded. If this is your 4th unit, you may want to look at your environment as well (well ventilated, good connections, etc) I'm not saying it couldn't be the unit. It took directv 14 units to get 3 working, and since I've had 2 HR20-700 refurbs that were unstable and were quickly replaced.
It might be in your best interest to invest in an external drive solution for the HR20. I, however, would be calling customer retention and having a calm, but stern chat with them about this.