VST's seen in Plug In Manager but not showing up in Instruments list

I am using Cubase 13 Pro with Windows 11.It just seems lately I have been having problems getting new VSTs to show up on the MDI instruments list. Even when they are put into the same folder as other ones that are showing up and showing up in plug in manager. Rescanning doesn't find anything. It seems more complicated than earlier versions or am I missing something?