If none of the above worked, the configuration file might be corrupted.
Steps to resolve (try in order)
Sometimes the installation "thinks" the MIDI is in one place when it's really in another. Toontrack support often recommends clearing the registry path to force a reset: Topic: no midi library found - EZdrummer Help - Toontrack ezdrummer 3 no midi library found
If you’ve moved your library to an external SSD, EZdrummer might have lost the trail. Navigate to the (the gear icon or dropdown menu). User MIDI and Linked Folders Add Linked Folder If none of the above worked, the configuration