Totally my fault in clicking "Cancel" when asked to Migrate from X2.  Shouldn't I be able to delete a file, like an INI, or other that would cause X3 to attempt the migration?

What do you mean by migration?  If you want to use all your old plugins and data etc, just install X3 using the same data paths you have for X2.  Select Custom Install when you run the installer to specify which paths to use.

X3 is ALREADY INSTALLED.  I should be able to delete a setup file and the next time I open X3, it will act as if I've never used it before & ask to migrate settings from X2.  (Instrument definitions, file paths, Preferences, etc)
 

If I were you I'd uninstall X3 and start again.
 
This time don't click cancel.

Since no one had the elegant (simple) way to fix this, I grabbed the sledgehammer and Unistalled X3, then reinstalled it.  Not only did nothing migrate, I now can't select my audio interface in Preferences.  I'm worse off than I started.  Is anyone awake yet at Cakewalk?

sailorted53@gmail.com
Is anyone awake yet at Cakewalk?

Technical Support phone hours are 1 PM - 6 PM Eastern Time, Monday through Friday. 617.423.9021 (Boston), 323.370.6701 (Los Angeles). They should be able to tell you what bits to move over from your X2 installation.
 
When you say you can't select your audio interface, do you mean it doesn't show up, it's grayed out, or the protocol (e.g., ASIO, WDM) isn't available?

My audio interface (DuoCapture EX) shows up grayed out.  THE ASIO is there and selected.
I'll be calling support at 1:00.

Have you tried holding down the shift key and then start SONAR the does an affective reinitialise. 

Shift-start did say it would reinitialize, but didn't really change anything.  Still no instruments or interface selectable.

Re-personalizing by holding the SHIFT key while starting SONAR copies will add any missing files to your user directory. It will not re-initialize based on a previous version. If you have custom instrument definitions they will be in the Master.ins in the previous versions user directory located in "your user directory\AppData\Roaming\Cakewalk\the previous version of SONAR." The file can be copied to the X3 user directory.
 
The DuoCapture is grayed out because another ASIO driver is selected. Deselect the other driver and the DuoCapture will be available.