Android TV & Google TV
Any app that doesn't come from the Play Store needs a one-off permission before the TV installs it. The permission is given to a single app, in this case Simple Downloader, which then may install things; nothing else on the TV changes.
When the install is blocked, the TV shows a message saying the app is not allowed to install unknown apps. Select Settings on that message.
A list of apps opens. Find Simple Downloader (or whichever app you are installing from) and turn its switch on. Press back; the installation carries on.
If no message appeared, open the same list by hand. The path differs between TVs, so try these in turn:
Settings → Apps → Security & restrictions → Unknown sources
Settings → Device Preferences → Security & restrictions → Unknown sources
Settings → Apps → Special app access → Install unknown apps
If the Settings screen has a search box, typing unknown gets you there fastest.
Use this only if the list is missing, your app isn't in it, or the switch refuses to turn on. Some devices, in particular the Chromecast with Google TV and the Google TV Streamer, hide the permission until developer options are on. Older Android TV sets usually don't need this.
Open Settings and find About: under System on Google TV, under Device Preferences on older Android TV, or straight in the main list on some brands.
Scroll to the bottom. The last line is Android TV OS build (just Build on older devices). Select it and press OK on the remote repeatedly. After a few presses the TV counts down ("you are now 3 steps away from being a developer"); keep going until it says you are a developer. Seven presses in all.
Now go back to the first or second way above: the switch is there.
Installing apps from outside the Play Store is a normal Android feature; every other app store works this way. The permission covers one app only, Google Play Protect keeps checking the device as before, and you can switch the permission off again once Smartcric is installed.
← Back to installing Smartcric on your TV
Other devices: Android app · Android APK · iPhone & iPad app · Android TV app
Stuck? Write to [email protected], say which phone or TV you have and what you saw on screen.