When you forget to turn on your interface first and then launch Sonar and get the message box "There are no audio devices for the current driver model..." do you
 
1. Shutdown Sonar, Start your interface and re-launch sonar
2. Turn on your interface and wait for it to be recognized "Do you want Sonar to Add this Device Now?"
 
I always close the app and restart, but I was curious for your answers. Or is there some faster way?

either way works. usually, I do 2 with my current interface.

I go with option #1: start over. It may just be a quirk of the driver, but with my particular interface, letting SONAR detect and add it often causes the buffer size, clock source and channel names to revert to default values. It's less of a hassle to just exit SONAR and restart it.

Not sure. My Layla 24 hasn't been turned off for 7 years.

I get this warning when I open two apps trying to use the ASIO driver.

Close Sonar, turn on interface, re-open Sonar.
Then I have to go into prefs and reassign my 1884 control surface settings; PITA.
Wish Sonar would ask if you want to close without any changes.
 
Tom

soundtweaker,
 
What is the advantage of leaving your interface on? For me, it would be a considerable waste of power when not in use. My interface is physically warm when simply powered on. I know some tube devices like to run warm, but a modern interface?

Option 1 for me just so I feel I have a 'Clean' start up.

Bibs

Option 1. However I don't forget very often.  Thank goodness. 
 
 
 
Then I look around the room and make sure no one is there and then pretend I didn't do that!

Option 1.