When an card game is over, the screen fades to grayscale and you return to the deck select and play button screen.
Sometimes the screen is stuck in an endless loop of firework animation while in grayscale and screen blurred.
Manual click doesn't help the screen progress... Softlock.
The feature:
Hearthranger is able to detect if Hearthstone is stuck on a screen more than 5 minutes.
Then... Hearthranger quits the game and relaunches it from the Blizzards Battle.Net Launcher.