This is a bit confusing and annoying, I use castle as my main base, before I took the castle I was able to assign Preston to guard duty.

At the castle it don't work and he is farming all day, same with the other followers.

However I found I could assign Pipper to anything even caravans.

I think this is some messed up flags, Had looked better if you could assigned some of the more combat oriented followers as guards.

Assigning, I'm kind of stuffed at the moment, I'm not a leader, far too low a Charisma. Hope your problem gets sorted though.

try assigning him to tend a plant. wait 24 hours in game, then re-assign to guard post.

I accidentally assigned Macready to work a Trade Booth. Now I can't UNassign him. Nor can I ask him to rejoin me. I'm thinking the way to do that is to assign some other settler to that same booth.

Actually you should avoid assign companions and other important (v.i.w - very important wastelanders) npc to traders etc. If you cannot unassign, remove the tradepost at night. You may need to wait a little before the changes come in action.

Cheers,

-klevs

I do not have local leader, and have no trading booths, but do those need to be built? If so couldn't you just scrap the one he is assigned to, then build it again and assign someone else? Or no?...just a theory..

Trade booths are expensive, not just in materials, but especially in bottlecaps. And I am of the opinion that only the Level 3 (Emporium) booths are worth building. ("Bigger is Better.")

Trade booths at multiple settlements boost Morale at each settlement AND can provide cashflow and a steady supply of ammo (Weapons booth) and raw materials (General Store booth). Expensive initial investment, but well worth it in the long run.

hmm...I will probably be getting into it soon, after reading about this new patch that is coming out, it sounds like some major improvements in settlement stuff...thanks for the info, I didn't know any of that before..