Hey,
I did this from this post:
and reboot about 5 times and use Appcleaner from freemacsoft and install it three times and reboot again 
and suddenly it works again.
btw there was a button in finder when I go to the seadrive folder it says upgrading seadrive… and after I delete seadrive with appcleaner it show me the very first time a button with something like „delete seadrive“ I pushed it and says yes and after another reboot and installing it works.
hopefully anybody can follow my thought and describing and it helps!!!
thanks to Jonathan