I have had TiVo on Comcast for a few years, and I had no trouble with this. About a month and a half ago, I got a new TV and a new connection. I don;t know if this is a coincidence, but my TiVo started malfunctioning. If I want to rewind a live broadcast, it will only go back 10 minutes. Once I rebooted, and it seemed to go back to normal, but soon it was back to the 10 minute limit. I had Comcast change the box, and I have the same problem. It also rarely records suggestions, and, if it does, it deletes them almost immediately.
Can anyone figure out anything about this?