Failures cluster into a small number of causes, and almost all of them are visible months before the end.
Running out of cash. The proximate cause of nearly every failure, though usually not the underlying one. A business can be profitable and still die here — see [cash flow and profit].
No real demand. The founder built something they were confident about without testing whether anyone would pay. The tell is a long build with no customer contact.
Customer concentration. One client at a large share of revenue is not a triumph, it is an exposure. When they leave, restructure or simply pay late, the business has no time to react.
Founder fallout. Two or three people start something with a verbal understanding, and there is no agreement about equity, roles, what happens if someone leaves, or who decides. When it matters, it is too late to write.
Growing too fast. More orders means more stock, more wages and more work done before payment. Growth consumes cash, and a business can be killed by success.
The founder as the bottleneck. Everything routes through one person until nothing can happen without them, and they burn out or simply cannot get to it.
Almost all of these are diagnosable early. The reason they are not caught is that the founder is inside the business every day and nobody outside is asking.
Identify the *underlying* cause rather than the symptom. 'Ran out of cash' is how it ended, not why.