I wonder if anyone can help. When I switch on / add another MIDI controller, say M-Audio Code 61, the MIDI inputs and outputs in existing tracks are reassigned and so sounds a mess. I can't find anything about this on this forum but have a vague recollection of this issue before. It adds the new controller in the middle of the list and so shifts the order off by one. Hence the reassignment. Hope I have explained it clearly. Up to date with Sonar and Windows 8.1.

yup, same thing here. It happens if you get the Sonar prompt asking you if you want to add the devices. The only way around (and not to screw things up) is to close Sonar, turn on all controllers, and then relaunch it. Quite annoying. 
 
Nick

Do you want to replace the existing controller with a new one, or supplement the existing controller with a new one? I don't know much about replacing but if I'm supplementing, and check both devices in Preferences, settings stay the same. Then I hold Ctrl while selecting the new controller as an input, and it becomes the input. The output and patch assignments remain the same.
 
I'm not sure how much of this is a SONAR issue and how much is a USB issue because (for example) I have some USB peripherals that Windows recognizes only if they're plugged in during power-up, and others that are recognized only if you plug them in while powered up. What I've found with SONAR is it seems to like having the controllers you want to use connected and turned on prior to opening the program. Hope this helps.

Thanks for the help. I suspect that it is the desire to have them all switched on when starting up. I have a lot of USB peripherals connected to my system (extra drives, dongles etc.) so I try to keep the ones I'm not using switched off.