Cubase lags

Cubase pro 12 have lag when I want to clic on Media tab , and when I want to put a plugin during a playback of the tracks, and especially on Start for scan of VST3s (I have cleaned all my VST2 version of the VST3 that I own but the time to scan VST3 is very looooooonnnnnnng) and also to duplicate a track.
I have a big PC (i9 9900K with 32 Go RAM and an Antelope Discrete 4 which works fine in thunderbolt) so I think it’s not my DAW which is in cause, but some improvement for performance seems to be mandatory on the 12th. and I’m not the only one who experience lag on scan of the VST3 at Start some friends of me have the same issue.