Scott,
I’ve recently purchased a new 16′ mbp and in the process of setting up all apps, etc. I’m now onto SD3. All my sounds are on an external drive and I recently downloaded the SD3 program. When launching it, I received the error message “no EZX’s or MIDI libraries were found in the selected folder”
When you say “try uninstalling the plugin” what exactly are you referring to? Uninstalling the SD3 program? 
Do I even need these libraries?
Thanks in advance.