This question already has an answer here:
I have just upgraded my system but it boots to Low Graphics mode by default. I have seen questions on how to solve this problem and they all suggest to run a couple of commands from a command-line interface.
But there isn't any command-line console by default in Low Graphics mode and hence, I cannot run those commands. And, the answers I saw to solve the problem doesn't explain this situation either.
How to switch to a command-line console in order to run the commands in Low Graphics mode?