Streamline will not install from the Twitch Launcher
In some cases, Streamline has difficulty installing from the Twitch Launcher. This is most likely due to pop-ups being disabled in a user's browser or an ad blocker being used.
Chrome users have particular difficulty due to that browser's built-in pop-up blocker. When using Chrome, a red "X" will appear at the top of the browser window, and the user can click on it to allow the pop-up that was blocked. Downloading the game from the Streamline details page seems to eliminate the pop-up blocker. (Please note: If you are purchasing the game with the intent of supporting a specific Twitch-partnered broadcaster, you should enter the URL of the Streamline details page along with the streamer's Twitch user name as follows: https://www.twitch.tv/directory/game/Streamline/details?br_name=BroadcasterName)
Some users may also experience problems that can be resolved by uninstalling and reinstalling the Twitch Launcher. You can find detailed instructions for doing this on the Twitch Support Center webpage.