It's a hard learned lesson that the UI tools can fail you at some point with Linux. At which point you are going to have to resort to the command line to fix it

It's a hard learned lesson that the UI tools can fail you at some point with Linux. At which point you are going to have to resort to the command line to fix it or just reinstall everything from scratch. A lot of people do the latter. Learning to fix things will get you familiar with the command line in a hurry.