You have to be a high enough level for it to appear, or spawn, apparently and I was at Level 28 when I did this.
It seems to be a matter of luck getting this armour, which I think should not come into a video game.
I completed dozens of missions for the ungrateful Brotherhood Of Steel of Danse's group and wondered why I was not being offered promotion or armour? I then realised I was being sent to places they had previously sent me to?!
Other than caps and XP there was not much reason to persevere for so long with that one, still it was not boring. Lol.
I also do not remember having this X-01 armour in the previous Fallout titles, do not know if it was available or not? I amm sure I remember seeing it somewhere?
Not played the game using it yet and interesting to see if I can change to a human companion and get them to enter the old T-51 Armour? I will find out tonight to see if I can get Piper in it?
Ooh not much space is there Piper? Lol.
I am beginning to appreciate, however, the sheer amount of buildings within the game making things look bigger than they are and there seems to be a myriad of places to find.
I would have still liked the map bigger, mind you.
One thing I liked about New Vegas was the absolute desolated wasteland combined with a desert and sheer open spaces along with the mutated wildlife. Not many additions to the wildlife in Fallout 4 and still no Iguanas! BOO!
Anyway the armour was found in a building called Court 35 and not marked on any map and west of Clock Towers, I think it was called. Or west of that building you get sent to by the Brotherhood Of Steel with the funny french sounding name, Fenuil Hall, or something similar, lol.
Here is a video at any rate ...
I am publishing this before it has uploaded so if your here really early you might want to come back in a couple of hours?! Lol. I have to head out of the house as ususal ...
It will post automatically on YouTube ..