CLM Acronym, stands for "Career Limiting Move." Originated at Microsoft. Signifies a mistake or decision that eliminates any hope of promotion or advancement within your field.Everyone makes mistakes. It doesn't matter what you do.
Some mistakes only affect yourself. Some mistakes can cost millions of dollars. Some mistakes can lead to lives being lost.
Personally, I believe that almost all mistakes are opportunities in disguise. A person can grow by learning from a mistake, processes can be strengthened as a result of the mistake, and if a mistake is properly handled, a mistake can actually lead to positive PR.
Of course, there are some mistakes that are just too large to be looked past. Sometimes, mistakes like that can lead to termination. Other times, mistakes end up being something that seems worse when you are going through it: the dreaded CLM. A good example would be Gumpei Yokoi from Nintendo. Even though he had guided several successful products to market (including the GameBoy, the Metroid series and others), the Virtual Boy was a large enough disaster that it essentially ended his career at Nintendo.
Nintendo saw the value of having him there, but also did not want to give him an opportunity to fail on that large of a scope again, so he was pulled out of a position of authority and relegated to being a "respected elder." In other words, he was essentially left in the middle of Nintendo with no responsibilities and was essentially useless.
CLM's are a difficult thing to overcome inside a company. Generally, if you are able to overcome the CLM, the people that you worked with in the past will have passed you internally, so any support structure that you may have had is essentially gone. It can be even worse if you decide to jump ship and go to a different company, because you'll be starting from scratch with no support structure.
So what do you do if you believe that you have committed a CLM? The first thing to do is to own up to it. People who take responsibility for their actions are generally able to overcome career obstacles like this easier than people who try to place the blame outside of themselves.
The second thing to do is to sit down with your manager to try to come up with a plan for how to rebuild yourself and move past this problem. "Made a mistake, but learned from it and moved past it" beats "made a mistake and wallowed in it for eons" any day.
The final thing to do is forgive yourself for the mistake. Most people who commit CLM's tend to dwell on them every day, and are constantly blaming themselves for the result. While one should never forget their mistakes, one should we willing and able to let go of any negative emotions surrounding the mistake.