OmniBox App Reset
Click Settings, then click Apps. On the right, click Running and then click All. Scroll down to find Omnibox TV Launch, and select it. Clear ONLY the cache (not data), and then Force Stop. Use the back button on the remote or the right hand side of the mouse to get back to the channel guide. Please note that you will now only use Clear data after all other options have been tried and when there is a problem with the subscription itself. After clearing the cache and forcing stop, this will launch the whole app fresh. See if that resolves the issue. If it didn't, then unplug the box and plug it back in.
Factory Data Reset
Click Settings, then click Backup & Reset. Select Factory Data Reset. Then click Reset Device.
This will only resolve issues with the software and should ONLY be done as a last resort. Get a pin or a paper clip. Then unplug the power cord from the back of the box and insert the pin or paperclip into the recovery slot. Still pressing in the recovery button, plug the power cord back in the box. Still pressing in the recovery button, power the box on. Continue to hold the recovery button (30 seconds-1 minute) until the “Green Android Guy” pops on the screen. If nothing appears on the screen, and it has been over a couple of minutes, work through the process again. If you release the recovery button at any time throughout the process, you must start from the beginning.