This topic probably isnt new but this is still an annoying glitch that needs to be patched asap. I miss going on a wasteland adventure without my bro Preston by my side

Can you details how you can't get him back as a companion after that quest? Maybe one of us can offer something you can try to get as a workaround.

Personally I've recruited all 11/12 companions, got max affinity with 8 of the them, I'm currently level 50. I have found that you need to be very extra careful with companions with Bethesda games (experience with FO3 and NV), I make new save, quicksave, at every dialogue stage, every time when I try to change companions, or recruit someone new or send anyone to any settlement, I double check and make sure they are there before moving on. I even went as far as avoiding the "change over" on the road, meaning I always do it all in the settlement where I keep all of them at one place, so they don't get a chance to get stuck on their way to where you send them.

If at any point they disappeared, and if you load to a new area/enter building, they are not there, you better reload and try again before moving on.

Sometimes when you already has that person as companion, when you need to talk to him about a quest, or turn in a quest, you need to get him/her to follow you first, fiddle around some companion dialogue, and finally you can talk to him about the quest.

So yes, get into these kind of play habits if you don't want to get glitched out without knowing then went on and play 30 hours more and then found out.

What happened was when i got back after completing a minuteman quest he told me its time to storm the castle and got right to it and left dogmeat behind because i had the minutemen this time help me. So i did the quest killed everything and got up to the part where he tells you to power the tower up. Did that he told me he cant thank me enough. Quest ends and i cant get him him anymore as a compainion . I tried reloading and doing different things before and during when the quest starts but everything leads to the same result. Im still playing and at lvl 50 but its fustrating i cant get him anymore.

Have you tried reloading to the point when he's still your companion? Before you start the "Storm the castle" quest? Or is that save too far in the past?

You can try to have him as your companion BEFORE starting and doing that quest, and finishing the quest, and see if he's still your companion?

If it's possible to reload to the save before all that, I'll definitely try it if you like Preston enough, let us know how it goes