After literally 10s of hours over a few weeks, resetting tivo, contacting comcast, talking to tivo reps, I finally found one tivo rep that actually looked up the issue. Apparently some comcast customers using tivo received messed up guide info, either from comcast or from tivo. A large number of channels will disappear from the guide and/or be listed as 'to be announced'. Many, if not most, seem to be HD channels. Some channels will show 'sign off'. Zap2it (whatever the site is ) will show the same messed up info for your comcast zipcode (to be announced channels will not show up, but the sign off channels will). After repeated attempts to get any answer from tivo they could only say they are back from vacation/holidays and are working on it. I should check back in a week to see if they are close. A week. For some of us, this started 2 1/2 weeks ago. So, no...it is not your tivo so do not waste time resetting it, redoing the guided setup, etc... Do not call comcast, waste of time (as usual). There is nothing you can do except call tivo and complain about nothing being done. Your cust rep will not at first look it up. They will attempt to help you fix the tivo and waste your time. Do not let them do this. Good luck waiting for the fix. Very annoying to lose so many channels for near a month on the guide. Good thing I don't use a dvr that needs that info...oh wait, it is a dvr and I do need that info. tired of missing shows.