Ok, so I had this problem on my old computer, and now I have it on this one too! So, I go to use the weapons manager, and it says no weapons manager, even with one on there, BUT the gui is expanded like it is open. So I have to switch from it to another vessel and back, and even then, when it shows the GUI, when I open the weapons, Guard mode, OR modules box, it expands to compensate for the size, BUT the weapons, guard mode, ore modules menu does not show up. SOS!! (P.S. It worked for a while, but after adding an unknown mod, it caused the gui to break on the new computer's install. Removing all the mods installed after it broke did NOT help.)