I’m playing through Fallout 4 again, and I’ve come across a bug in the game that’s preventing me from proceeding.
While playing the quest “Reunions”, I fought my way through Fort Hagen, all the way down to just before the boss fight with Kellogg.
Just before I engaged him, I went back to Sanctuary to drop some stuff, rest up, and grab some gear. Now that I’ve returned, there is a locked gate just as you enter the Fort Hagen Command Center, down the hall to the right.
The gate was open before, and there are dead synths all over from the last time I was there, but there is no way to open this gate now. It’s not controlled by a terminal or anything like that. In fact, I’m not sure I had to do anything special to open it before that I remember.
How do I get past this so I can fight Kellogg and complete the quest?