Perhaps Comodo should go back to doing public release candidates. This killswitch install failure is a pretty obvious problem that was caught almost immediately after release. Clearly internal testing isn’t cutting it. The regression from 12.3.3.8152 where unchecking “Rate applications according to their vendor rating” leaves the UI is also still present in the new release.
For anyone adventurous enough, you can copy the killswitch install files from the previous version and drop them in the Comodo program folder in safe mode and it actually works.