I had 1,5 year ago the same problem that the ur824 is looking for the soundcard when starting Sibelius(about 1,5-2 minutes). I looked in the forum of Sibelius and found my question to them and I saw that the problem was resolved because Steinberg had bring out a new driver. But now the problem start all over (for months now). This week I did a clean installation of windows 10. With only the ur824 connected to the computer, I installed the latest driver(with the latest firmware on board). After that I installed Sibelius 8.5.1, but the problem stayed. I also tried all of the usb ports 2 and 3. No results. I’m also now have problem with the latest Kontakt from native instruments. I just upgrade to Cubase 9, and than I don’t have this problem. So for some reason the UR824 will not reset or something like that.
Monday I called for support but I should get an email, but I didn’t recieve the mail yet. I’m a musician and have to use Sibelius every day several times a day so I hope you can resolve this!!
with regard Robert
Asus P8z77-v pro
24 gb ram