The problem is with the cable box that you happen to have from Comcast. TVGuardian simply reads the closed captions as they are streamed from the cable/satellite box to external devices, which is the TVGuardian in this case. Around 85% of the cable/satellite boxes in homes deliver the closed captions without errors and on time, and consequently work very well with TVGuardian. The other 15% deliver closed captions to external devices with poor quality and timing errors.

You might want to have Comcast swap your box for another model. We've had good reports on the Motorola 8300HD. Comcast uses different make and model boxes in different parts of the country, so you might have to try whatever other model they have in your area. Comcast will swap your box without charge.