I have an Axiom 61 USB MIDI controller.
Often I remember to turn it on only after being within a project in Sonar.
Sometimes Sonar can recognize the keyboard that was connected while running (hot swap), but sometimes not.
If Sonar can not, I'm forced to exit and run Sonar again.
I wonder if anyone knows how to solve it?

I think it may have more to do with the computer not recognizing it. Make sure the USB port isn't in the power-saving mode where it falls asleep if not used for a period of time.

Thanks, now it is working for days without problems.