1. The wrong cofounder(s)2. An uneven equity split3. No clear leader 4. Distractions5. Early acqui-hire6. Not understanding the problem7. Inability to handle the rollercoaster8. Out of control costs

Hollie Slade writes:

Right now, Y Combinator is wrapping up wading through 3000 applications for this summer’s intake, up almost 20% on last year. Just two percent of the 3000 will get a place. Although the incubator’s got a strong track record, some startups inevitably sink without a trace. Here, Jessica Livingston shared with FORBES some of the totally avoidable silent killers she sees every cycle.

What strikes me about Jessica's list is just how many things need to go right for a startup to succeed:

1. Right founders with a clear leader.

2. Right market.

3. Right focus.

4. Right ability to handle the roller coaster.

5. Right ability to control costs.

And even if you have those things, you need some luck.

It's amazing there are as many successes as there are.

It's just like learning to ride a tandem bike... it seems amazing that anyone can do it, until they do it.