[THIS WILL ONLY WORK FOR THE BLACKSCREEN BUG WHEN THE GAME CANNOT CONNECT TO THE SERVERS.]

First, you have to open the roaming folder. To do that, simply hold the windows key (Between Ctrl and Alt) and then press r. It will open a window that should look like this:













Write %appdata% and press enter
If you did it correctly the roaming folder should open.
In there you should find a folder called 'Warner Bros. Interactive Entertainment'.
Go there and open the 'LEGO MARVEL's Avengers' folder.

You should see another folder in there, called 'GUI3'.











Simply delete this folder or rename it to 'GUI3_Backup'. That's all you have to do. Lego Marvels Avengers will create a new one, that shouldn't crash your game. This fix worked for me in both Beyond Gotham and Marvel's Avengers!

If this worked for you, please like this guide and leave a comment if it didn't. Thanks :D