FYI, the correct procedure to re-install an app on Roku:
1) Remove the app (Highlight the app, press the Options (*) button on the remote, then Remove)
2) RESTART the Roku (Settings/System/System restart/Restart) <-- MUST DO THIS HERE!!!
3) Re-install the app
(Otherwise, settings/cached data associated with the app are left behind and it wont be a clean re-install)
Known solutions/workarounds for the YT app not loading:
1) Change your Theme to the Roku Default (Settings/Theme/Restore default theme) - try again
2) Change your Screensaver to a Roku clock (Settings/Theme/Screensavers) - try again
3) Check for updates (Settings/System/System updates/Check now) - try again
4) Remove YT app, RESTART ROKU (Settings/System/System restart), Add YT app - try again
5) Network connection reset (Settings/System/Advanced system settings) - try again
6) Completely unplug power from Roku for 10-15 minutes - try again
7) Factory reset (Settings/System/Advanced system settings) <--- last resort
