Critical error?

So i lost LP for this and im not entirely sure what it is any ideas? “A critical error has occurred and the process must be terminated. This is usually do to the result of incompatible 3rd party software being installed on your machine. Please disable any overlay, streaming, or experience ‘enhancment’ software. Additionally, you may need to whitelist this application with your security software.”

Also as a side note why is the client being a pain when trying to tab out ...