Now it happened again. 
Im working with a project with ten VST´s and it worked fine in several days, but then suddenly today there is a hearable latency from when I press the key until I hear the sound.
But I tried recording MIDI and the notes end up at the right place, but I hear the sound a little bit after so its awkward to play that way.
If i try reopening Cubase and the project its the same problem, but if I open a new project everything works fine.
Latency numbers in Cubase are the same as always, 6 ms.
And buffersize as I always have, 256 in RME UCX.
Kronos is master keyboard via Korg MIDI driver.
This is really annoying to have to copy evevrything into a new project.
Why is this happening Steinberg?
This kind of issues really kills music creativity!