I have an older synth that I've used for years for getting scratch sounds but now I want to retire it. The problem I have is I also have a Mackie Control. If I disable or turn off the synth and open a project that referenced its port, Sonar automatically reroutes the tracks to the Mackie Control which sends the faders on the controller into a tight oscillation loop. I think this is from messages Sonar sends out to initialize the patches on the missing synth. The only way I've found to stop this from happening is to remove the Mackie Control from the control surfaces list.
Is there a way to tell Sonar not to remap anything when the original MIDI port is gone?
 

Apparently this has been fixed in Platinum.
I was able to turn off my venerable Fantom X6 and uninstall the drivers. Opening projects that referenced it now brings up a missing port dialog, dismissing it without changing the port and routes the tracks to a MISSINGFantom port. My MCU no longer goes apesh*t. YAY! :)