Hi there, Thanks for reaching out. Please ensure you double check all possible Ghost locations again to determine and acquire the one you're missing. Note that it may be prudent to reload the areas once or twice to be extra certain they're not there and have already been picked up. Following that, you should just need to place the last one at the Outpost in order for the triumph to update. That said, if you check all possible Ghost locations and Outpost spots only for you to be unable to acquire or place the last Ghost, please capture some footage that demonstrates this. You can upload the footage to a public video hosting site, like YouTube, and we’ll be glad to take a look.