I recently got Horizons on my steam account (given it was on sale) yet every time I have tried to launch ED using Horizons, the launcher tells me the game needs an update, however there is no update on steam. The notice tells me to set update priority to high, which I have done. This changed nothing. The only option available is to close the launcher, even though the only way I can see to fix this is the big "install" button in the launcher, which the notice doesn't allow me to select (the only option is to exit the launcher).