I just did this mission that took me about an hour to kill the boss, just to find out I couldn't actually complete it because Preston Garvey doesn't actually show up. It tells me to meet the minute men in the courtyard but the quest marker is all the way at the first sanctuary. So I went all the way over there and he told me we still needed to take back the castle. Also, one of the quest steps still says I haven't completed it saying I still need to destroy all the egg clutches. I went over every single nest making sure I didn't miss them but its still very glitchy. Really don't want to do the whole thing again, any help?

I got the same problem just an hour ago. Try to install some generator to power the radio in the court as it is the next step to settle in here. Preston just appeared and I could finish the mission.

It actually fixed itself after 10 minutes of running around. Thank you, though.

For anyone else having the same problem, I did as well, I just went to another missions and started it. Once I did I got a notification that the Militiamen main guy wanted to see me at the castle. I wondered around looking for that missing egg cluster for hours until I finally started a new mission in frustration.

Cheers

I'm just going to reply in this thread because I am having a problem with completing this quest. It is a different problem then what you are encountering. The problem I have is that I am not allowed to build the Large Generator to power the radio even though I have the Science perk at Rank 2. The requirement to build the generator is Science Rank 1. I have all the materials necessary to build it. Due to this glitch/bug, I cannot finish any of my other quests that are related to Preston because there are no dialogue options and he keeps telling me to build the generator.

This entire chain seems buggy. I'm having trouble with the radio transmitter as well. I'm done with the old guns quest and my transmitter has enough power, but the NPC seems to have forgotten he is assigned to it. He won't broadcast and just keeps telling me to get the transmitter up and running (which it obviously already was or I wouldn't have gotten to the old guns quest).

The consensus seems to be NOT to tune into the radio signal during the quest and it won't bug out. If it's bugged, the only way to fix is to go to an older save and not do the optional part.

Very glitchy.

I was temporarily stuck here (in my case, I didn't have the required Science Perk) until realizing that I could connect two small generators to a pylon to create the required 10 units of power.

That was a minor delay compared to a Preston Garvey bug on this mission where I had to spend about 30 minutes figuring out that he'd wandered away and was in a random firefight with Raiders in the City. Then I had to get him back to the Castle. Fun.