Just found this slightly old thread... I just bought myself a Focusrite Scarlett 18i8, and during installation i experience the exact same problem as described above. And i am wating for support response...
Your solution seems to be to go back to driver 2.3.2, but i cant find it nowhere. (The actual driver is now 2.3.4). Any of you guys willing to help out to gimme a link, or e-mail the driver?
All the best
Bengt
Sweden
bengt.vallhagen@gmail.com