I have charter. Same problem, couldn't fix it with tv remote, had to use the charter remote. (1) Leave tv on, press cable button on remote and then power, this shuts off cable box. (2) Press menu key (3) First line showed 4.3 setting, I changed it to 16.9 (4) Second line showed HDMI cable at 480, I changed it to 1080. (5) Hit power button again, this should turn the tv back on. (6) Fixed my problem. (7) I think you also can call charter and tgey can help walk you through it. I didn't even know about the settings on my charter box until researching on the internet. I contacted insignia, they told me by using the cable box it overrides the tv settings. Hope this helps