The plug-in "Groove Agent SE" could not be found for Instrument Track "Groove Agent SE 01"!

Why is this happening, cubase 12.0.40 Mac M1

You likely didn’t install the latest version of your plug-ins from the Steinberg Download Assistant.

All bundled content can be found under the entry for your version of Cubase 12.

Hi and welcome to the forum,

Make sure, you have the very latest version of Groove Agent SE installed, please.