For me, this seems to happen when I have certain plugins in a project. So far in my testing, a few Waves plugins seem to create this effect. I close the program and it seems to close, but when I try to relaunch, nothing happens. I check Task Manager and Cakewalk.exe is still running, but now as a background process.
If I manually close it in Task Manager and reopen, it opens and works normally.
After a while, I got tired of this extra step and created a task in Task Scheduler that closes the program and all child processes, then created a shortcut to the task in my task bar. If I close the program using that taskbar link instead of the X or File menu in Cakewalk, it closes the program completely and then it will work when reopened.
The task I created is:
taskkill /f /t /im Cakewalk.exe