I don’t know what has gone wrong but all of a sudden I can’t start the game. I just get a message that the game has crashed. It is the first time this has happened.
Hi.
Open the Blizzard Battlenet desktop app, click the Hearthstone icon on the left, and select Show in Explorer from the Options menu.
In the Hearthstone folder, find the Output_log.txt and error.txt files. These are your error reports.
Paste the contents of the files to pastebin.com and provide the following link.
I just uninstalled and reinstalled Hearthstone and that made it work again…
I’ll do that next time it crashes.
Happy to hear that helped! 
Have a few seconds to spare? Let me know how I’m doing!