Have exact same problem. I have two basic $29 Roku boxes on two different TVs. I started having all audio go out on either TV at random. I was also unplugging power and plugging back in. However, I quickly learned I could go to the home page, click on "settings", then "system", then "system restart" and have same fix. It is easier than unplugging, but loss of audio will return and for me it is getting more frequent on both TVs. I am frustrated not being able to call Roku's tech support number and get some live help. They have not answered or opened those phone lines in months. Just today I went to try and trouble shoot on site myself and was directed to Home/Settings/Audio/Audio Mode...change to Stereo/ HDMI...change to PCM-Stereo and so I did that. I have my finger's crossed. Not sure I will buy more Roku devices with no tech support. I know this is not my WiFi or my two store brand (Best Buy) TVs. Frustrating and annoying problem. Shame on Roku for not being there for their customers.
