I had a similar problem with my TC 20 Professional Platinum for the past few years. Most of the times TurboCAD did not start at the first attempt.
Sometimes I had to start two or three times until it finally appeared.
If this was the case, the TC20 - process appeared in the taskmanager but not the TCStart - process. I than had to kill The TC20 process and retry.
I finally found the cause of this behavior. Upon Startup, TurboCAD makes a "call" to russia which my virus scanner (bitdefender) detected as malware and silently blocked it. Found those calls as I once looked through the protocols.
As I myself did not like that call as well, I learned to live with that strange behavior.
Since I have moved to another virus scanner a few weeks ago, TC starts properly every single time.
As I write these lines, I realize that about since then it seems that I get marketing mails from TurboCAD at least once a week.
Might be something similar in Your case.