This issue has nothing to do with the guide provider, it just appears to be because it is the most user viewable area that is effected. Vista by itself is losing the channel frequencies for specific stations at random timeframes. I have a strong suspicion that even if we had a legitimate Microsoft provided guide this issue would still be occurring (unless they'd caught it in beta testing - but I'm not sure they would have).
To prove this to you all:
Next time it happens and before fixing it, go into Settings/TV/Guide/Edit Channels, and if "Seven" (or the channel effected) is still listed but without a tick, and there is a "7" in small type next to it and no (at xxxMHz) frequency next to it, then Vista has lost the tuning frequency, not the guide data.
e.g. It will look something like this
[tick] 9 "Nine" (at xxxMHz)
[ ] 7 "Seven"
Seven would normally look like:
[tick] 7 "Seven" (at xxxMHz)
No tuning frequency, and therefore according to Media Center no channel, so therefore it doesn't display a guide for it. It's also why you can't just hit the channel number and tune to it.
These are identical symptoms to what happened with MCE2005 when we first got Rollup 2, and why just a few days later MS fixed it with a "Rollup for Rollup 2". Problem is, this time the issue isn't happening to everyone as consistently as then, so finding the root cause is taking MS time.
The Microsoft Media Center team are WELL AWARE of this issue, have test binaries in the field locally, and will hopefully have a fix for this soon.
Whilst I understand people are frustrated (I am!), pointing fingers at Ice for this problem isn't helping. Also be aware, this issue effects other guides as well, so moving away from Ice won't resolve this any faster.
Regards,
Shane.