Yaobing
Generally to get around the no signal problem I have to close mc20 and open again.
Same here except in my case it is not a "no signal" channel but a "low signal" channel. I have one channel that for some reason varies throughout the day from low to high signal strength. I have checked it on MS WMC Signal Strength test screen many times & it will vary from 1 bar (low) to 5 bars (good); while 6 bars is the best.
It seems that in many cases whenever MC TV encounters a low signal channel it will lock up (which is unacceptable behavior) requiring closing & re-load of MC.
This is one area where MS WMC does a better job as it simply blanks out (a totally black screen) all video & audio activity as the channels are being changed so if it encounters a low or no signal channel it simply ignores it & allows the viewer to move on to the next channel.
This is part of the same problem I had with slow (& locking up channel changing) when I was using Windows Default Direct Audio. When I went to WASAI it solved part of the problem as WASAPI (like MS WMC) stops all AUDIO playback on channel change but does little to nothing to stop VIDEO playback which still causes hiccups such as this thread is reporting on.
I firmly believe all playback (both audio & video) should be stopped on channel change. I know in my heart it would resolve the channel changing hiccups that I & the threads OP are having & will result in a much smoother channel change transaction.
Please consider this as a request.
Thanks