VST instruments not showing

When I go to Devices, VST instruments, nothing shows up.
I have EZ Drummer and Superior drummer installed and I can still hear the drums in existing projects but I can’t edit them due to the above problem. I’m using Artist 6.
Any idea what the problem is?
Thanks

Must be using Instrument tracks and not MIDI. Read up on the difference.

They were working perfectly well then just disappeared for no apparent reason.
I haven’t changed anything - just opened up an existing project (which contains superior drummer) and suddenly I can’t open the vst instrument dropdown menu.

Anyone?

Can you check if the vst box is hidden somewhere or minimized in such a way that it is not visible?