I've searched and read the troubleshooting info found at tivo.com. I'm not finding anything quite like my current issue. A couple days ago, my Series 4 began freezing/hanging intermittently. It always happens when the remote is in use: changing channels, finding recorded shows, etc. I changes the remote batteries which did not solve the problem. The remote does not seem to be the issue, because even when the Tivo is frozen, the TV still responds to the remote (on, off, volume). The only way to unfreeze the tivo is to unplug it. Overheating crossed my mind, so I also confirmed that the fan is working. The amber light on both the remote and on the tivo both glow when buttons are pressed. Oddly, the unit appears to continue recording, even though it is unresponsive to the remote.
Would appreciate any advice. Thanks in advance, jim