I got my Tivo tv box in early October last year and set it up as per instructions.
As I watch television rarely I didn't use the tv until 1 January this year to watch a program, I got a message stating that as the Tivo box has not been used for over 30 days an upgrade/update was needed.
The upgrade started and took over 4.5 hours to complete and it goes without saying I missed the program. When the upgrade was completed I didn't have any sound for the programs, but other devices attached to the tv work perfectly.
I followed suggestions to change the HDMI cable, this had no effect. I have reset the Tivo box several times without success.