TopBar Not Disabling???

03:57:57.869 - SetCore: TopbarEnabled has not been registered by the CoreScripts

03:57:57.870 - Script 'ReplicatedFirst.LocalScript', Line 4

03:57:57.871 - Stack End

Is the error for the script without the pcall. It also doesn't get rid of the top bar.

wait()
script.Parent:RemoveDefaultLoadingScreen()
	local starterGui = game:GetService('StarterGui')
	starterGui:SetCoreGuiEnabled("All" ,false)
	starterGui:SetCore("TopbarEnabled", false)

The script with the pcall also doesn't work. there is no error as expected but it doesn't get rid of the top bar like it should.

wait()
script.Parent:RemoveDefaultLoadingScreen()
pcall(function()
	local starterGui = game:GetService('StarterGui')
	starterGui:SetCoreGuiEnabled("All" ,false)
	starterGui:SetCore("TopbarEnabled", false)
end)

Why is it doing this????