In the new Cakewalk, in Edit>Preferences>Control Surface,my stalwart Mackie is not showing as an option to select.  Any ideas?

If you mean that when you click "Add new/controller surface" button, it's not in the list then it sounds like your MackieControl.dll is missing or hasn't been registered.
 
The easiest way would be to re-install CbB.
 
If you don't want to do this however, you can try this:
 
1. Make sure MackieControl.dll exists in C:\Program Files\Cakewalk\Shared Surfaces  - if it's not there, you can either re-install CbB, or download it from here: https://github.com/Cakewalk/Cakewalk-Control-Surface-SDK/tree/master/Bin/x64
 
[Edit]: If you want a more up to date version, you can download my own version of this which has both mine & Azslow3's fixes for ProChannel EQ & Compressor support : https://github.com/msmcleod/Cakewalk-Control-Surface-SDK/tree/master/Bin/x64 
 
2. Open a cmd prompt as administrator, and type:
 
regsvr32 "C:\Program Files\Cakewalk\Shared Surfaces\MackieControl.dll"
 
 

Thanks for your help Mark.  I got it sorted out now.