I traveled to The Castle and completed (I thought) the Taking Independence mission. However, the goal 'Destroy the egg clutches' returned' and has remained, even though I have thoroughly searched the whole location inside and out and cannot find a single egg.

Since then, Preston Garvey follows me everywhere. Dismissing him makes no difference. Indeed, I have to ask him to follow before I can then dismiss him. Asking another companion to join me makes no difference. I just get two people following me!

I have tried reloading games, but because I kept trying to get rid of him, I have no saves from before this began. I've tried turning off the game and restarting it but it makes no difference. It is driving me crazy, because I have the Lone Wanderer perks and I can't stand Preston Garvey.

I have put so many hours into this game, but I'm on the verge of just quitting it because I cannot get this idiot to stop following me. Can somebody please help?

Have you tried just killing him? I don't know if it'll work or if you'll become banned from the Minutemen or not but you could try it and see if it gets rid of him.

He cannot be killed. You wear down his life, he crouches for a few seconds and then gets up and acts like nothing happened. I even pushed him off the Prydwen, but as soon as I went through the next door he was there.

I don't think companions can die in Fallout 4 and, as the game insists he is my companion no matter what, he's immortal.

Oh I misunderstood you. I thought you meant he was just "following you around" for no good reason. That is pretty annoying I know I had some issues with Dogmeat where he wouldn't take any of my commands so I switched him out for Codsworth.

Well, I'm out of ideas! I tried getting dismissing Garvey, getting a new companion and then fast travelling with the new companion. Garvey was still there! I got so annoyed, that I just shot him and shot him until he actually started shooting back. I hurried away and he didn't follow - then, the very next loading screen later, there he was... waiting for me. Like nothing had happened.