I'm having the "channel is not authorized" problem, but mine seems more severe than any other reports I've seen. I have two TiVo Premieres, with cablecards from Comcast, and it's happening on both of them, at least a dozen times a day. But it DOESN'T happen simultaneously. Frequently, one TiVo is working just fine, when the other isn't. Sometimes it's only a few channels that become not authorized; sometimes it's all non-local channels. It affects both SD and HD channels. The second interesting factor is that the problem often (but not always) happens exactly on the hour, even though there hasn't been an automatic channel change (say, to record something on my schedule). I'll be watching a two-hour movie that started at 9:00, for instance, and suddenly, just as the clock changes from 9:59 to 10:00, without warning, the screen freezes and the "not authorized" message pops up. Other times, however, the problem DOES occur just as I'm changing a channel. The third interesting factor is that when the problem occurs, I can fix it EVERY TIME, without fail, by simply going to the cablecard menu in the Settings section and choosing the Test Channels function. The channel may or may not appear correctly during the test function, but as soon as I exit the test and press the LiveTV button, it's back -- until the next time it happens, which may be only a few minutes later. The fourth interesting factor is that this seems to have started right about the same time as I upgraded my Comcast service to add some additional channels several weeks ago. I've called Comcast when the problem happens, and they've tried resetting the cards, but this does not help. They've offered to let me have new cablecards, which I'll probably try, but I'd really like to know if this is a problem with the cablecards, with the TiVos, or with errant signals being sent out by Comcast that somehow disable the cards temporarily. I tend to think it's not the latter, since I'm able to fix the problem without contacting Comcast via the Test Channel menu as described above. This is really driving me nuts, since any of my programs aren't being recorded that happen to be not authorized at the time of the recording. Any ideas/suggestions? Until I really know where the problem lies, I'm afraid it's going to stay a finger-pointing game between Comcast and TiVo.