Why isn't this clone script not working on ROBLOX Player while it IS working on ROBLOX Studio?
Please provide more explanation in your question. If you explain exactly what you are trying to accomplish, it will be much easier to answer your question correctly.
function a()
local plr = game.Players.LocalPlayer
if plr.PlayerGui:FindFirstChild("UI") then
print(plr.Name.." already has the UI")
else
script.Parent.UI:Clone().Parent = plr.PlayerGui
end
end
script.Parent.ClickDetector.mouseClick:Connect(a)