I find a solution in order the cubase to recognize the spectralayers as an ARA after the update to newest version of spectra.
- go to the C:\Program Files\Steinberg\SpectraLayers 12\ARA-win\VST3 and there you will find the folder spectralayers.vst3 (folder no dll!) rename it Spectralayers (that means you delete the text .vst3)
- go to the C:\Program Files\Common Files\VST3 and find the folder spectralayers.vst3 (folder no DLL!) - do the same.
- Run Cubase - it will pop up an error about spectralayers. Continue, now you can see the ARA extension if you click in any Audio.
- close the cubase, unistall the spectralayers 12.
- Manually delete the folders of spectralayers in both locations program files/steinberg/ and common files/vst3
- Install Spectralayers 12 from the Steinberg download assistant
- You are good to go.