Well this is a strange one.
Right click (to delete) the track, and Cakewalk blinks out of existence.
Everything is setup and working but there are two null Kontakt tracks that refuse to delete, and when trying to delete crash Cakewalk.

Please share the project file and the crash dump and we can investigate.

Thanks Noel, Where is Core crash dump?
%AppData%\Cakewalk\SONAR Platinum\Minidumps
C:\Users\name\AppData\Roaming\Cakewalk\Cakewalk Core
Cakewalk disappears, blinks out of existence, there is no visible error, so It needs manual locating.

Are the "null" tracks still connected to instances of Kontakt, or have they already been removed? Strange things can happen when you have a source or destination that's no longer valid, especially with orphaned instances of Kontakt. If they're still there, try deleting them via the Synth Rack with the "delete associated tracks" option checked. You could also try changing the tracks' routing before deleting them.
 

The instances are deleted from the synth rack, but the "null" tracks remain and when I right click to delete, Cakewalk blinks out.

sadicus
The instances are deleted from the synth rack, but the "null" tracks remain and when I right click to delete, Cakewalk blinks out.

Try Archiving them?