My technical co founder was a former coworker. I had to fire him because he was lazy and incompetent in numerous ways. We move in the same tech circles. Is there any way to let others know to avoid him that won’t make me look bad or get me sued?

I'm missing something here. You fired your cofounder and this person has nothing to do with your ongoing viability as a company, and you're now worried about ensuring that this person is unhirable by others?

Your job is not to warn off the world. In fact, I'd say that's pretty petty of you. If you get a reference call, you have every right to be honest - especially if asked would you hire this person again. Other than that, you wasting cycles on this means you're not working on your business.

Ditto the previous commenter.

The thing that puzzles me though is he was a former co-worker? Doesn't it bode badly for you that you couldn't tell he was a slacker then?

Extremely similar thing happened to me. It's better to let it go. I know that's easier said than done. I truly ate crow because I always spoke positively about him and it took everyone by surprise when I got tired of excuses. Then, the anger set in because I was upset with myself. Then I was upset he was such a p^@sy that he didn't quit when he knew his own level of incompetency. Then, it moved into acceptance that I needed to be a stronger manager and that he was never capable of doing the job in the first place and I should have followed my gut when I realized it. Typing about this drums up memories of his fanboy behavior, but what makes it all feel better is knowing that - 1) if he succeeds in his new startup, he would have to have learned from his previous mistakes or he would have actually taken on a job that he can do. I've already learned from my interaction so thanks for the lesson. 2) if he fails, he will never work in this town again because he would have burned two well connected startups and advisers and investors are always watching. Plus, relocation fees are extremely pricey! If you're still uneasy about things, go out and dominate with your new company so that you can make him re-think his laziness and ability to work within his competency... Plus, there's nothing better than watching the look on his face when your new guy pulls up in a tesla and a smile on his face from work/life balance because you're one of the highest paying employers in the country.

If you're this upset, he may be too. Leave him alone and he'll leave you alone. Lol!!!

Seriously, same thing happened to me, but I'd call him sketchy, emotionally immature, and incompetent which translates into my poor judgment of others. I take ownership because I'm the one that allowed him on my team in the first place. It hurts me a lot because I felt that it was a waste of time and money. Lost 2 major potential customers as a result and am completely sickened by the fact that I was never asked for a reference, but truly that was best because it wouldn't be fair. The way I truly see it is this - I'm going to succeed regardless. He will always need a job. He's an employee type not a boss type. If for whatever series of events take place to put him in a leadership roll for his own company, he will raise 100 million, IPO with an under performing stock price and learn what it's like, he'll sit back and watch me in my billion dollar company with a $1700 per share value and wonder why he can't reach a billion. He may call me and ask and I will say, remember when you we were younger and thought you knew everything? Remember when you were so busy not listening to instruction and not taking initiative to deliver the product requested? Remember when you went bonkers in the meeting? Remember when you behaved differently in front of certain people because of their job title in an effort to throw me under the bus? Thank you for that lesson, it helped me get to where I am today. But, there was also a lesson somewhere in between there for you too. Apparently, you missed it. Sweet dreams.

That fantasy phone call makes all the pain go away. Like the fantasy, nothing else matters outside of the reality you paint for yourself. Don't paint yourself as the only victim in the situation, be honest enough to know you were accountable too for not calling him on his sh&t. Be thankful for the lesson and move on.

I know it's easier said than done, believe me, I'm still hurt, but that phone call.... :-)

Don't say anything bad about him/her. If someone calls for a reference just say you will not give a reference.

Karma. Karma will take care of it without your help.

Stay. Classy.

-Mr. Miyagi

Think about all of the time and energy you'd waste telling people anything. When someone wants to know another's reputation, they'll ask for it.

This is not your problem. How old are you???